Then, as now, Des Moines was a safe, wholesome city. The streets were long, straight, leafy and clean and had solid middle-American names: Woodland, University, Pleasant, Grand. (There was a local joke, much retold, about a woman who was goosed on Grand and thought it was Pleasant.)

It was a nice city—a comfortable city. Most businesses were close to the road and had lawns out front instead of parking lots. Public buildings—post offices, schools, hospitals—were stately and imposing. Gas stations often looked like little cottages. Diners (or roadhouses) brought to mind the type of cabins you might find on a fishing trip. Nothing was designed to be particularly helpful or beneficial to cars. It was a greener, quieter, less intrusive world.

Grand Avenue was the main artery through the city, linking downtown, where everyone worked and did all serious shopping, with the residential areas beyond. The best houses in the city lay to the south of Grand on the west side of town, in a hilly, gorgeously wooded district that ran down to Waterworks Park and the Raccoon River. You could walk for hours along the wandering roads in there and never see anything but perfect lawns, old trees, freshly washed cars and lovely, happy homes. It was miles and miles of the American dream. This was my district—South of Grand.

The most striking difference between then and now was how many kids there were then. America had 32 million children age 12 or under in the mid-1950s, and four million new babies were plopping onto the changing mats every year. So there were kids everywhere, all the time, in densities now unimaginable, but especially whenever anything interesting or unusual happened. Early every summer, at the start of the mosquito season, a city employee in an open jeep would come to the neighborhood and drive madly all over the place—across lawns, through woods, bumping along culverts, jouncing into and out of vacant lots—with a fogging machine that pumped out dense, colorful clouds of insecticide through which at least 11,000 children scampered joyously for most of the day. It was awful stuff—it tasted foul, it made your lungs chalky, it left you with a powdery saffron pallor that no amount of scrubbing could eradicate. For years afterward whenever I coughed into a white handkerchief I brought up a little ring of colored powder.

But nobody ever thought to stop us or suggest that it was perhaps unwise to be scampering through choking clouds of insecticide. Possibly it was thought that a generous dusting of DDT would do us good. It was that kind of age. Or maybe we were just considered expendable because there were so many of us.

The other difference from those days was that kids were always outdoors—I knew kids who were pushed out the door at eight in the morning and not allowed back in until five unless they were on fire or actively bleeding—and they were always looking for something to do. If you stood on any corner with a bike—any corner anywhere—more than a hundred children, many of whom you had never seen before, would appear and ask you where you were going.

"Might go down to the Trestle," you would say thoughtfully. The Trestle was a railway bridge over the Raccoon River from which you could jump in for a swim if you didn't mind paddling around among dead fish, old tires, oil drums, algal slime, heavy metal effluents and uncategorized goo. It was one of ten recognized landmarks in our district. The others were the Woods, the Park, the Little League Park (or "the Ballpark"), the Pond, the River, the Railroad Tracks (usually just "the Tracks"), the Vacant Lot, Greenwood (our school) and the New House. The New House was any house under construction and so changed regularly.

"Can we come?" they'd say.

"Yeah, all right," you would answer if they were your size or "If you think you can keep up" if they were smaller. And when you got to the Trestle or the Vacant Lot or the Pond there would already be 600 kids there. There were always 600 kids everywhere except where two or more neighborhoods met—at the Park, for instance—where the numbers would grow into the thousands. I once took part in an ice hockey game at the lagoon in Greenwood Park that involved 4,000 kids, all slashing away violently with sticks, and went on for at least three-quarters of an hour before anyone realized that we didn't have a puck.

Life in Kid World, wherever you went, was unsupervised, unregulated and robustly—at times insanely—physical, and yet it was a remarkably peaceable place. Kids' fights never went too far, which is extraordinary when you consider how ill-controlled children's tempers are. Once when I was about 6, I saw a kid throw a rock at another kid, from quite a distance, and it bounced off the target's head (quite beautifully I have to say) and made him bleed. This was talked about for years. People in the next county knew about it. The kid who did it was sent for about 10,000 hours of therapy.

With respect to accidental bloodshed, it is my modest boast that I became the neighborhood's most memorable contributor one tranquil September afternoon in my 10th year while playing football in Leo Collingwood's backyard. As always, the game involved about 150 kids, so normally when you were tackled you fell into a soft, marshmallowy mass of bodies. If you were really lucky you landed on Mary O'Leary and got to rest on her for a moment while waiting for the others to get off. She smelled of vanilla—vanilla and fresh grass—and was soft and clean and painfully pretty. It was a lovely moment. But on this occasion I fell outside the pack and hit my head on a stone retaining wall. I remember feeling a sharp pain at the top of my head toward the back.

When I stood up, I saw that everyone was staring at me with a single rapt expression. Lonny Brankovich looked over and instantly melted in a faint. In a candid tone his brother said: "You're gonna die." Naturally, I couldn't see what absorbed them, but I gather from later descriptions that it looked as if I had a lawn sprinkler plugged into the top of my head, spraying blood in all directions in a rather festive manner. I reached up and found a mass of wetness. To the touch, it felt more like the kind of outflow you get when a truck crashes into a fire hydrant or oil is struck in Oklahoma. This felt like a job for Red Adair.

"I think I'd better go get this seen to," I said soberly, and with a 50-foot stride left the yard. I bounded home in three steps and stepped into the kitchen, fountaining lavishly, where I found my father standing by the window with a cup of coffee dreamily admiring Mrs. Bukowski, the young housewife from next door. Mrs. Bukowski had the first bikini in Iowa and wore it while hanging out her wash. My father looked at my spouting head, allowed himself a moment's mindless adjustment, then leapt instantly and adroitly into panic and disorder, moving in as many as six directions at once, and calling in a strained voice to my mother to come at once and bring lots of towels—"old ones!"—because Billy was bleeding to death in the kitchen.

Everything after that went by in a blur. I remember being seated with my head pressed to the kitchen table by my father as he endeavored to staunch the flow of blood and at the same time get through on the phone to Dr. Alzheimer, the family physician. Meanwhile, my mother, ever imperturbable, searched methodically for old rags and pieces of cloth that could be safely sacrificed (or were red already) and dealt with the parade of children who were turning up at the backdoor with bone chips and bits of gray tissue that they had carefully lifted from the rock and thought might be part of my brain.

I couldn't see much, of course, with my head pressed to the table, but I did catch reflected glimpses in the toaster and my father seemed to be into my cranial cavity up to his elbows. At the same time he was speaking to Dr. Alzheimer in words that failed to soothe. "Jesus Christ, Doc," he was saying. "You wouldn't believe the amount of blood. We're swimming in it."

On the other end I could hear Dr. Alzheimer's dementedly laid-back voice. "Well, I could come over, I suppose," he was saying. "It's just that I'm watching an awfully good golf tournament. Ben Hogan is having a most marvelous round. Isn't it wonderful to see him doing well at his time of life? Now then, have you managed to stop the bleeding?"

"Well, I'm sure trying."

"Good, good. That's excellent—that's excellent. Because he's probably lost quite a lot of blood already. Tell me, is the little fellow still breathing?"

"I think so," my father replied.

I nodded helpfully.

"Yes, he's still breathing, Doc."

"That's good, that's very good. OK, I tell you what. Give him two aspirin and nudge him once in a while to make sure he doesn't pass out—on no account let him lose consciousness, because you might lose the poor little fellow—and I'll be over after the tournament. Oh, look at that—he's gone straight off the green into the rough." There was the sound of Dr. Alzheimer's phone settling back into the cradle and the buzz of disconnection.

Happily, I didn't die, and four hours later was to be found sitting up in bed, head extravagantly turbaned, well rested after a nap that came during one of those passing three-hour moments when my parents forgot to check on my wakefulness, eating tubs of chocolate ice cream, and regally receiving visitors from the neighborhood, giving particular priority to those who came bearing gifts. Dr. Alzheimer arrived later than promised, smelling lightly of bourbon. He spent most of the visit sitting on the edge of my bed and asking me if I was old enough to remember Bobby Jones. He never did look at my head.

Bill Bryson lives in England with his wife and children.

Copyright © 2006 by Bill Bryson. Adapted from the book The Life and Times of the Thunderbolt Kid by Bill Bryson, published by Broadway Books, a division of Random House, Inc. Reprinted with permission.