I'M GOING AWAY AGAIN, the fourth foreign trip in as many months. My passport has another new tattoo, my arm another needle hole, my vaccination record another stamp. I bought a new journal, the empty pages beckoning like a sculptor's block of clay.

I've read handwritten reports and obscure books and corresponded with one of the few people on earth who's been to the region of China's western Sichuan province where I'm going, 71-year-old Japanese explorer Tomatsu Nakamura. I've printed out the Landsat photos and managed to obtain the uncannily accurate Soviet topos that have guided me on so many trips before.

Before he died in 1995, along with his brother and two friends, when a bowhead whale capsized their boat in Baffin Bay on their way home from an expedition to the Barnes Ice Cap, my best friend, redheaded Mike Moe, told me that "half the joy of a journey is planning it; the other half is coming home and bragging about it." I remember so many nights when Mike and I spread maps across his living-room floor and dreamed big about some distant place; three months afterwards we'd be giving a slide show about our adventure in that same living room, roasting each other to the hooting of close friends. Later, when everyone was gone, we'd stretch out on the rug and plan our next trip.

I have been going away and coming back since I was 16. I blew off my last semester of high school so Mike and I could escape to Europe and Africa and Russia. We traveled till our money ran out, then kept going, scrounging meals in university cafeterias from Seville to Stockholm. Eight months later we made it back to Wyoming to start college.

During my junior year, when I met Sue, the woman who would become my wife, the first thing she and I did was take off to the Grand Canyon for ten days. Two months later I left for three months to bicycle across the U.S. When I returned, we moved in together—Sue was the first woman I'd met who was secure enough to accept my wanderlust and not see it as a threat to our relationship. Several months later I left for a month to ski across Yellowstone, and Sue left to bicycle Europe for six weeks.

Here, gone. Back, gone again. I chose this recursive path, and it has been my life and livelihood for more than two decades. I can't get enough of the world: the stench of sweat on a Tanzanian bus, the sword of wind on an Andean pass, a little girl in the Sahel carrying her baby sister on her back and a bucket of brown river water on her stiff-necked head.

My gusto for journeying and writing about it has remained inextinguishable—and yet something else, something corded to travel like ligament to bone, has changed over the years: my connection to home.

In my twenties I hardly gave a thought to home. I was wild and self-centered and left without a look back. I remember standing around a campfire in the Tetons, snowflakes hooking together in midair and parachuting to the ground. One of our clan had just learned that his girlfriend was pregnant.