"It's a mystery to me how anybody among us develops a social conscience," observes Nichols, a prolific novelist (The Milagro Beanfield War) and nonfiction author (Keep It Simple: A Defense of the Earth) who has long been a writer of powerful conscience. He begins this short memoir—part of Milkweed's Credo series, by authors of "deep conviction"—with his upper-middle-class childhood, with parents who were deeply engaged in both politics and the natural world. After the 1969 publication of his first book, The Sterile Cuckoo, Nichols traveled to Guatemala, where the poverty he observed and his meeting with political activist Michael Kimmel (now dead) turned him into a political radical. Firmly believing that industrialized countries enslave the poor and plunder the planet to maintain their wealthy lifestyle, he has since devoted his life to redressing this global economic imbalance. Some readers may be put off by the book's relentlessly lecturing style and self-satisfied tone. The latter is compounded by the laudatory portrait of Nichols by Credo series editor Scott Slovic, which concludes the volume. Recounting Nichols's fragile health (he has a serious heart condition), Slovic also describes with awe Nichols's very simple existence: he lives alone near Taos, N.Mex., in an apartment lit by a bare lightbulb. Still, his fans—and many activists—will enjoy Nichols's essay, which the author describes as a "plea for social commitment." B&w photos. (July)