BOOK REVIEW / NONFICTION : A Global Trip With a Biker of Industry : INVESTMENT BIKER <i> by Jim Rogers</i> ; Random House $25, 416 pages

Jim Rogers is filthy rich--or, rather, road-dust rich, since this self-made multi-upon-multimillionaire recently celebrated what he calls his “freedom from capital” by going on a global odyssey with his companion, Tabitha Estabrook.

In some ironic ways, Rogers’ saga is no different from that of any other menopausal male: 50 looms in front of him like a monolith, so he hooks up with a woman about half his age and hits the road. What separates him from others in the not-so-young and restless population is that he’s made it, and then some.

Rogers--like Willy Loman’s brother, Ben, in “Death of a Salesman”--walked into the jungle of the stock market as a young man, and when he walked out at 37, by God, he was rich. As half of the insanely successful Quantum Fund in the 1970s, he’d made money all over the world. So, in 1980, he retired.

Ten years later he was prepared to survey what was essentially his domain; the countries where he’d either made money already or thought he might make more in the future. He intended to circle the globe--west to east across Eurasia and China, east to west across Siberia, back to Ireland, from the top of Africa to the Cape, through Australia’s desert, and from Argentina to Alaska. If that wasn’t challenge enough, he planned to do it on a motorcycle.

This book is the chronicle of that trip, which reads something like “The Wall Street Journal Goes Around the World in Eighty Days.” Rogers certainly is interested in adventure; the man is rich enough to buy the countries he’s attracted to and persuade them to relocate near his front yard, but instead he goes through countries that even poor people wouldn’t normally pick as a vacation site.

He is at his bike’s mercy, but he has an imperial manner, so Estabrook, the pragmatist and bike novice, trains as a mechanic; theoretically, she can solve any problem that comes up.

But theory is not practice, and understanding a bike is not the same as being experienced either as a driver or maintenance artist. In what seems to me some of the most revealing material in the book, the early days involve a lot of Rogers looking in his mirror and not being able to find his traveling companion.

She can’t quite keep up with her road-seasoned pal--and although he castigates himself when he’s done dusting her off, a few days later he’s showboating again and wondering if it was a bad idea to bring her along.

The travelogue is leavened with Rogers’ observations on which foreign countries are worth investing in and why, as well as historical anecdotes. Rogers is the sort of cowboy who makes for fascinating reading, but I find myself wary of him at the same time. “If you want to change your life,” he writes, “do it.” Nice advice from a man who probably could squander money for the rest of his life and still come out ahead; not quite so functional, perhaps, for a regular Joe or Jane trying to make ends meet.

Rogers has an emotional epiphany during his journey and decides he’s ready for a committed relationship, but perhaps the right woman just hasn’t come along. For now, he is a man without obligations, a man who never has to ask himself the question, “What if?”

And he seems vastly entertained by his life--a happy enough situation for anyone to be in, but finally, more of a fantasy than a fact. Read him for fun, for the vicarious thrill of a wanderer’s life from the comfort of your armchair, but don’t go cashing in the kids’ college fund to buy up real estate in Zambia.