Each weekday morning, around eight thirty, I walk half a block down the road to the mailbox kiosk the six houses on our side of the street share.

A few weeks ago, on my walk to retrieve our mail, cool morning air, I noticed there was something on the sidewalk in front of my neighbor's home.

Something alive.

At first, I thought it was an unusually large insect.

It took me a moment, walking closer, to register what it was, because I never expected to see one on a sidewalk. Just like if I looked out my kitchen window it would take me a moment to process that the gray bulk moving by was an elephant.

If something's where it's not expected to be, it's hard to see it.

What I was staring at, on the sidewalk, was a crawfish.

Crawfish are freshwater crustaceans that look like miniature lobsters. They live in the mud around ponds and rivers. Usually, they grow about two inches long before they're harvested, rinsed, sold.

This crawfish was three times that size, long as my thumb from tip to wrist.

I felt sorry for it.

It had a beautiful, mottled, ivory and orange shell. Its bigness made me wonder if it had thoughts.

What was it doing out in the middle of nowhere, on a sidewalk?

Did it jump out of a grocery bag jiggling in the back of a passing car? Drop out of an airplane? (its lightness might have helped it survive the fall).

The nearest pond was five hundred feet away, behind all these homes, across the street, down a long, gentle green slope of mowed grass.

The crawfish was still alive, trying to get from the lawn side of the sidewalk to the grass strip bordering the curb. But how would that help it? It needs mud (crawfish are referred to as "mud bugs").

Each early Spring, April, live crawfish are available everywhere in Texas. They're like zucchini in California. We've bought big bags of crawfish in the past, brought them home, little lobster claws slowly opening and closing within the orange netting, scissored through the top of the bag, dumped five pounds of live crawfish in our stainless steel kitchen sink.

You've got a hundred orange creatures suddenly aware they're in a new environment, crawling slowly over each other's backs. A hundred thought bubbles thinking, Does anyone know which direction is home?

The first thing you do with live crawfish is put a large pot of water on to boil. You pick each crawfish up by its shelled back, feeling the flexings, drop it in a colander until the colander's half full (although to the crawfish, the colander's half empty), hold the colander under tap water to rinse away the mud. One or two big brutes in each batch, twice the size of the others, will raise their tiny Popeye dominant claw as if that's going to save them. It never does.

They go from dripping colander to boiling pot. After two minutes under the bubbles, one by one floating up, on their backs, small pinchered souls rising to crawfish Heaven, they're ready to be scooped out and dumped, steaming, into a large bowl, motionless and bright red.

You do the same thing with the next colander-full, and so on, until you're down to a dozen crawfish lying on the bottom of your stainless steel sink, pretending to be dead.

Unlike most animals, crawfish play possum.

The dozen in the sink look dead, and of course you wouldn't want to cook a dead crawfish, who knows how long ago it died, they deteriorate quickly, like lobster, but if you poke at them a couple of times with an index finger, most will admit they're still alive. In a five pound bag, we've usually only found two or three who are truly dead, I assume from tiny, tiny heart attacks.

The water the crawfish have been boiled in, by the time you finish, is almost black. Rich as it is, I never trust it in this unfiltered state, because the crawfish have so much mud in their bodies, released when they're boiled. We strain the stock several times, through doubled-over cheesecloth, until the center of the cheesecloth holds a thick dark paste lightly decorated with detached legs and antennae.

As nonchalantly as we perform this wholesale boiling, "murder in the kitchen", this one huge crawfish on the morning sidewalk gave me pause. I certainly wasn't going to eat it, any more than I would eat a white bag of McDonald's french fries I found lying on the sidewalk, but I didn't see how I could save it, either. I suppose I could have. Mary and I could have driven to the large pond behind our home, dropped it in the water, but we didn't. We were in the middle of making club sandwiches, and no one wants to eat cold bacon.

So I left it there.

Went the rest of the way to the mail kiosk, slipped my key into the lock of our chamber, pulled out the mail, mostly bills, when is it ever anything else, walked back, passing the crawfish again. He hadn't made any progress.

Birds on the opposite sidewalk.

The next day, Friday the 13th, the morning meteorologists were standing in front of their weather maps, talking excitedly about a huge, ferocious weather system about to move into the Dallas area.

It always interests me how meteorologists "come alive" whenever bad weather is expected. I sincerely feel for them. Week after week they have to say things like, Highs today will be in the mid-eighties, with overnight temperatures reaching down to the mid-forties. Day after day after day. Imagine how boring that must be? And you have to repeat that dull announcement every ten minutes. Highs today will be in the mid-eighties, with overnight temperatures reaching down to the mid-forties. Plus you have to banter with the news anchors, with their more expensive haircuts, who are telling viewers a breaking news story about the CEO of a local company who went crazy and chopped off the heads of his family. What a tragedy. I have to stop and wipe my eyes. So anyway, What's the weather like today, Brad? Highs today will be in the mid-eighties, with overnight temperatures reaching down to the mid-forties.

But then, a few times a year, blue skies turn dark, and the meteorologist opens the newscast, elbows out, jaw squared, and you can tell he's thinking, Today, I'm the star! All eyes on me.

And that's the way it was this Friday the 13th. Everyone on the morning news was deferring to the weather guy. And he no longer had a thirty second segment. He was talking on and on. Repeating himself. Digressing. Everything was permitted. Tornadoes might happen. Not just pea, marble, or golf ball sized hail, but baseball sized hail. The sky is going to kill people today.

The floor tiles in our master bathroom were clammy to our bare soles, from the humidity of the approaching storm. We discussed where we would barricade ourselves and our cats inside our home if a tornado did strike near us. We decided on the garage, because then we'd have the added option of barricading ourselves, if the garage roof flew off, in our car, much like the strangers in Night of the Living Dead, barricaded in the farm house, had the extra option of barricading themselves in the basement. You have to occasionally think about things like that in Texas (when a tornado is near, the sirens go off in town as a warning, and concurrent with that, all the telephones in the house start ringing, which has only happened a few times in our fifteen years here, but when it does happen, we look at each other and our faces are not happy.)

Later that night, listening to WRR, the classical music station, to track the storm's progress, I started defrosting the shrimp we bought a week earlier from Whole Foods.

We buy from Whole Foods because the shrimp isn't treated with chemicals to preserve its shelf life (chemicals that give shrimp a nasty, ammonia taste). Whole Foods' shrimp are sweet-flavored.

The shrimp we buy comes in a four pound frozen rectangular block, from Vietnam. You tear off the black and white cardboard container, slip away the interior heavy clear plastic wrapping, and you're looking at a block of frozen ice about fourteen inches long, six inches wide, three inches thick.

Through the ice of the block you can see rows of shrimp, very neatly arranged, curve to curve to curve, as if spooning each other, about a dozen shrimp to a row. There's a middle row that's hidden, and of course a row on the other side of the ice.

We generally eat a pound of shrimp per meal, so we needed to partially defrost the shrimp to separate them into four piles.

That's my job.

Defrosting the block of shrimp takes patience, because a lot of tap water has to flow down over the block before things even begin to loosen, but it's that best kind of patience, where there's no frustration at all, just a sense of quiet wonder watching how things slowly change.

The shrimp themselves have an H.R. Giger color to them, looking black and brown when you first pick up the block, but you realizing, as you balance the block under the tap, their colors are really greens and yellows.

The excitement in defrosting the block starts when enough ice has melted between the humped backs of the rows of shrimp to where the first one, always at one or another end, never in the middle, starts to loosen. You can hold the multi-legged edge of that shrimp in your fingers, feel its coldness, and wobble it slightly, like a long, loose tooth. Even at this point, it might be another five minutes before the shrimp has unmoored itself enough from the others in the row to actually pull free.

It may be another five minutes before the next one loosens, but by then, so much tap water, the rest in the rows start giving up, a minute between each release, then forty-five seconds, then, towards the end, an entire jigsaw section detaches, three or four shrimp frozen in interesting orgy positions.

There were tornadoes that night, but thank God, not down our street. The mailbox kiosk was still there the next morning, though elsewhere, especially in nearby Fort Worth, the tornadoes, over and over, touched down. On the morning news, the weatherman gestured at his map, which showed clear skies. Highs today will be in the mid-eighties, with overnight temperatures reaching down to the mid-forties. The morning anchors were back in charge, introducing clips of the storm's damage, people trying to be brave in front of huge piles of structural debris that had once been their homes. Another clip showed an aerial view of a church that had had its roof completely removed, as if it were a dollhouse, you could look down inside from the helicopter view and see all the pews still neatly in space, rows of them, like our frozen shrimp. Even the lectern was still standing, but no one to preach.

The following Tuesday, April 17, was the fifth anniversary of Mary's stroke.

Once Mary was out of the intensive care ward, then out of the hospital, then out of the year or so she spent in therapy, six hours a day, five days a week, I enrolled her in an outpatient therapy program at Baylor. I'd participate in the first hour of each day's therapy, which was one-on-one, but for the second hour, which was group therapy, upstairs, I'd stay downstairs, in the building's large waiting room, reading one book after another I brought from home. I usually sat at the back, by these beautifully carved bookcases from a better age, shelves filled now with Readers Digest condensations of bestsellers. We had entered the world of illness. During the hour I read, other people would wander in, in family units, the multi-generation group focused on helping the one family member with physical problems slowly sit down on one of the sofas, or wheel their chair over to an area of the large room where the sun wouldn't be in their eyes.

During this period, I had a Philip K. Dick moment.

Dick was a post war science fiction writer. Most of his work featured one protagonist or another who gradually became aware that the world around him, that he took for granted, was not real, but rather a construct created for one purpose or another. He was a great writer. If you're not familiar with him, start with the novel, Do Androids Dream of Electric Sheep, later made into the film Blade Runner, not a bad movie, but infinitely inferior to the novel.

And after you've read a few Dick novels, by all means read the letters, published by Underwood-Miller, collected so far in five volumes, with a sixth, presumably final volume, due soon. The letters give you a true sense of who he was as a man, not always that nice a person, but who is, all the time? One of the letters I always remember when I think of Dick is in Volume Four, his February 27, 1975 letter to Robert Jaffe. For nearly all his life, Dick relied solely on the earnings he received from his novels, which meant he was horribly poor, often having to borrow money from others. By 1975 though he was starting, finally, to get well-known, and in fact The New Yorker had sent someone out to interview him for an upcoming issue. To be interviewed by The New Yorker not only meant his book sales would increase, but was an acknowledgement from the publishing establishment he desperately wanted (throughout his professional life, he chafed at how he was classified as a science fiction writer, rather than a "serious" writer). He bragged about the upcoming interview. You can feel the pride in his letters to his circle.

Finally, the interview was published.

Here's how he describes it in the letter to Jaffe:

Anyhow, I thought I'd write you and thank you for writing me and also mention that The New Yorker interviewed me, in the February 3 issue; did you catch it? And the issue before they called me "great". (This was all in the "Talk of the Town." In the interview they called me their "favorite science fiction writer," and said I was "bearded, jolly, and tubby," which caused one chick I know to wince, pointing out that now The New Yorker can't interview Santa Claus without repeating itself style-wise.)

I always feel sorry for Dick when I recall that letter. His big moment, when he's expecting to finally receive some praise after all his years of suffering, and they call him fat.

But he handled it well. At least in that letter. One can only imagine how he actually felt when he eagerly opened his copy of the issue, scanned the piece, saw the insult.

Anyway, my Philip K. Dick moment was set in motion when Mary and I arrived at Baylor one morning for a therapy session, and there was a small sign outside the ground floor men's room announcing the room was closed until further notice, for renovations.

For the next few months, I had to use the elevator to go up to the second floor whenever I had to pee.

Spring turned into Summer. Still that sign was there. More and more busted-up material from inside lying outside the door, wall tiles and porcelain toilets, mirror shards and aluminum stall handles, waiting to be hauled away, hammers and drills heard behind the door.

Finally, in Fall, Mary and I are walking hand in hand down the wide corridor of the building towards the rear, where the one-on-one therapy was conducted, and the sign was gone.

After the session, I took Mary to the elevator, waited until she started to rise for her group therapy, then went into the men's room.

I didn't have to use the bathroom. I was just curious to see what they had changed.

Nothing.

Having pushed into the bathroom at least once a day for so many months, I knew how many sinks there were, how many urinals, how high the mirrors behind the sinks rose, the style of the faucets, the color of the stall doors, the type of ceiling lights, and it was all exactly the same. I mean, exactly.

For all that work, all those months, something must have changed. But nothing had.

And then the frightening thought, the Philip K. Dick moment: Had there really been months when the bathroom was closed for renovations, or was that just a false memory implanted in me?

Mary showed me a Yahoo! News item about a new exo-planet that had been discovered orbiting around Gliese 581, a star in a nearby galaxy. ("Exo-planet" means a planet orbiting around a star other than our own sun-i.e., a planet outside our solar system.)

The planet is the first one discovered that is close to Earth's dimensions (most exo-planets that have been discovered are gas giants, like Jupiter). In fact, the newly-discovered planet is about fifty percent larger than Earth, and is being referred to in the press as a "Super Earth".

Its surface temperature ranges from 32 degrees Fahrenheit to 104 degrees Fahrenheit (between 0 and 40 degrees Celsius), which means that in terms of temperature, it is certainly capable of supporting life.

Whether or not it has an atmosphere or magnetosphere that would allow life is still unknown, but the early reports are promising.

The planet, named 581c, is a little over 20 light years away, in other words, about 120 trillion miles away (193 trillion kilometers).

We don't currently have the technology to send a probe that vast distance, but someday, we will. In the meantime, there's a lot we can do, and will do, here on Earth, to learn more about 581c.

Of all the bodies we've discovered, 581c is the one most likely to have life, and not just microbes.

The Science Channel is running a new series called Planet Earth. Narrated by Sigourney Weaver, each show focuses on a different aspect of life on Earth, from forests to jungles to fresh water, oceans, caverns, and other environments. The series was five years in the making, and includes the most stunning photography I've ever seen in a nature series. It's incredibly moving to see the wide diversity of life on our planet, under all sorts of adverse conditions. If our own home hosts this range of life, imagine what another world such as 581c might. The series also made me realize once again how precious animal life is, and how threatened by us. I don't want a future like Dick's novel Do Androids Dream of Artificial Sheep, where virtually all non-human animal life is extinct, and people have to content themselves with mechanical animals.

The historian Felipe Fernandez-Armesto has a new book out, Pathfinders: A Global History of Exploration. William H. McNeill reviewed the book in the April 12, 2007 issue of The New York Review of Books.

Here's a quote from the book that struck me as an original way of looking at history:

History has two big stories to tell. The first is the very long story of how human cultures diverged-how they parted and developed differences, in ignorance or contempt of one another. The second is the main subject of this book: a relatively short and recent story of convergence-of how human groups got back in touch, exchanged culture, copied each other's lives, and became more like each other again.

Such a powerful idea of what history is really about. Not just this great man, that great dynasty. We started as one, then became many, but now are working our way back home, to one again.

Space exploration will help complete that reunion with ourselves. Its expense requires cooperation. There are no Americans in deep space. Only humans.

Our cats are strictly indoor cats. They never, ever go outside. They don't have front claws.

Every once in a while, as a treat, we let them go out into our garage, opening the door between our utility room and the garage. They hear that doorknob sound, that hinge sound, and they gallop down from wherever they are in the house, a small herd heading out into what we call their backyard. There's always something fascinating going on out there, like an upside down June bug hanging from an abandoned web, or a black garbage bag filled with the aromas of a hundred weeds or a hundred crawfish.

We have seven cats.

Sheba, an orange tabby, came to us through our backyard. He used to live in a stand of tall cannas we have in our garden, back in 1996. Eventually, as the weather started getting colder, we scooped him up and took him inside (I still have a long, white scar on my right forearm from our first, unsuccessful, attempt to rescue him.)

Years later, after Mary's stroke, we took in another stray, a gray cat named Lady, squat face like a tiger, who turned out to be a Trojan horse (she was pregnant with five kittens, though we didn't know it at the time.)

If Augustus was, as I believe, the greatest politician who ever lived, Sheba was the worse.

He terrorized Lady while she was pregnant, it never dawning on him she was about to give birth to five guided missiles. If he had been a little nicer, maybe licked the top of her head occasionally, he'd probably be top cat today. As it is, whenever he makes his wary way through the downstairs rooms, he gets bitch slapped by Lady's progeny.

Whenever we do let our cats out into the garage, Sheba never, ever goes out there. Probably he figures he'd get trapped out there by the others, far from us.

But the other day, we're getting ready to close the door to the garage, check to see if anyone's still out there, and lo and behold, there's Sheba, all the way at the front of the garage, by the shut door, looking worried. I didn't even recognize him at first, because I never expected to see him there.

I can't tell you how shocked we were. It was as if he suddenly started talking about English muffins.

I walked over to him. His aloneness reminded me of the crawfish on the sidewalk.

I bent over, picked him up in my arms. He immediately started purring.

We brought him back to where he's safe, we brought him home, but didn't eat him.