Naj, a Wall Street Journal writer born and raised in Bengal, travels in Central and South America and the US Southwest in pursuit of pepper specialists and special peppers--all of the hot, capsaicin-endowed varieties known to most of us as chiles. Naj tramps the Andean foothills of Bolivia--a likely candidate for the birthplace of hot peppers--with a botanist seeking the mother of all chiles. He is drawn to the Yucatan by haba§ero, a Mayan staple and the hottest of all peppers. He visits the McIlhenny Company of Avery Island, Louisiana, and digs up ugly controversies surrounding its jealously protected trademark tabasco sauce. He attends a National Pepper Conference in North Carolina, and visits pepper farmers, tasters, breeders (of ``designer chiles''), pathologists, pharmacologists, and enthusiasts in Texas, New Mexico, and elsewhere. Naj's account of all of this goes down easily; and a chapter on peppers' appeal, including speculation on the ``pepper high'' and its possible addictive qualities, has a special interest for the growing cult of North American chile users. His botanical information, though, isn't much help in sorting out the different varieties and names; at times, he seems to toss off peculiar statements of fact without much questioning or trying to reconcile or even cite his sources. Still, an agreeable assemblage of lore and field reportage.