As the 50th anniversary approaches of the crash of a so-called extraterrestrial craft near Roswell, New Mexico, the UFO conspiracy theory is getting more attention. These latest books approach Roswell from different perspectives but identical agendas. Hesemann and Mantle are young UFO researchers who have visited Roswell and spent several years collecting documents and eyewitness testimony from people reputedly involved in either the crash recovery or its cover-up. (Most of the eyewitnesses turn out not to be.) The authors trade off chapters, with Hesemann using his anthropologist's training not only to tie the Roswell crash to Native American legends but to claim that Egyptian hieroglyphics and the Greek alphabet are directly related to the characters said to have adorned the crashed spacecraft's exterior. Corso, a career military intelligence officer, claims to have managed myriad research projects throughout the 1950s connected to recovery of the Roswell craft. Like Hesemann and Mantle, he asserts that the Cold War was a cover to develop "alien technology" that superpowers USA and USSR could not only use against the other but against the threat of extraterrestrial invasion. The most memorable passage in either book, however, is Hesemann and Mantle's suggestion that President Clinton induced the warring parties to make peace in the Bosnian war only by showing them proof of that alien menace. For public libraries convinced that pro-UFO books are needed for balance, the Hesemann and Mantle may be appropriate. The Corso is only for the few special libraries that have made documenting the unconventional a collecting priority.Scott H. Silverman, Bryn Mawr Coll. Lib., Pa.