"It is as big and depthless as the sky itself. You can see the curve of the earth on its surface as it stretches away for miles to the far shore." So begins Old Glory, in which Jonathan Raban recounts his eye-opening descent of the Mississippi River in a 16-foot aluminum motorboat. As the English author explains, his obsession with the subject began with Huckleberry Finn, which he first read as a 7-year-old. And in fact, his opening sentences refer as much to the imaginary river as to the real one, which turns out to be less bucolic than Raban expected. Three miles upstream from Oquawka, Illinois, he's nearly pulverized by a towboat. Later on, the intrepid voyager only just manages to escape a treacherous whirlpool near St. Louis, calming himself afterwards with a generous dose of tobacco and Valium.

True, when Raban isn't cheating death he encounters some stunning terrain, which he describes in no-less-stunning prose. Yet Old Glory is much, much more than a travelogue. It is also a brilliant interrogation of the American psyche, in the tradition of De Tocqueville and Crevecoeur. And ultimately, Raban tells us a great deal about the very phenomenon of travel, with all its rigors and rewards, and its peculiar, metaphysical dislocations: "Riding the river, I had seen myself as a sincere traveler, thinking of my voyage not as a holiday but as a scale model of a life. It was different from life in one essential: I would survive it to give an account of its end."