In i978, I began a series of journeys across the United States in the company of geologists, with the purpose of doing a piece of writing that would describe not only the rock exposed in roadcuts but the geologists with whom I travelled. The result was meant to be a sort of cross section of North America at about the fortieth parallel, and a picture of the science. On (and away from) Interstate 80, I travelled for a year, sometimes traversing the country all the way, but generally covering a zakelijke energie segment with this or that geologist-with Professor Kenneth Deffeyes, of Princeton University; with the sedimentologist Karen Kleinspehn, then a Princeton graduate student and now a professor at the University of Minnesota; with Anita Harris, of the United States Geological Survey; with David Love, of the Survey; and with the tectonicist Eldridge Moores, of the University of California, Davis. At the end of that first series of’ trips, after I transcribed my notes and developed a structure for the over-all composition, I discovered that I had outlined something that would keep me writing for more years than I wanted to spend consecutively on the subject. The structure had four main sections, which stood apart as well as together, so I decided to write them at intervals, always turning to other fields before returning to geology and to more wanderings with the respective geologists. The additional travel led as far away from Interstate 80 as mainland Greece, the island of Cyprus, a mining camp in Arizona, and the San Andreas Fault from end to end. The topic reached beyond the American cross section into world ophiolites and global tectonics. It somehow involved Robert Louis Stevenson, Chief Washakie, and Theodore Roosevelt (twice). It somehow involved Winona of the Lenape, William Tecumseh Sherman, William Penn, and Johann Augustus Sutter. The controlling element-the theme that guided the basic structure-was plate tectonics. The plate-tectonics revolution had occurred in the nineteen-sixties, and when I set out on my travels the concept was not without detractors. I wanted to see who was opposed, and why, and in what ways the new theory was being tested and applied. There would be plenty of other matters discussed, but plate theory was paramount. The structure is not linear-not a straightforward trip from New York to San Francisco on the interstate. It jumps about the country. For example, it begins in zakelijke energie vergelijken New Jersey and leaps to Nevada, because the tectonics in New Jersey two hundred million years ago are being recapitulated by the tectonics in Nevada today.