Science/sf writers Bova and Preiss present a wide-ranging discussion of mankind's search for alien life, along with an intriguing section on how amateurs can help scan for signals from distant planets. The search for alien life-forms has long had its committed enthusiasts. Many of the better known aficionados are represented here, attempting to define alien intelligence, debating the issue's relevance, lamenting a previous lack of political savvy in raising funds for research, and reporting on the recent progress of SETI (the Search for Extraterrestrial Intelligence project). Bova begins with a methodical discussion of how scientists narrow down the number of stars likely to foster life (as we imagine it) to "only a few billion." Bruce Campbell, head of the High-Precision Stellar Velocities Group at the Univ. of Victoria, points out that there is as yet no hard evidence for the existence of even one planet outside our solar system. Isaac Asimov; dolphin-communication researcher Diana Reiss; and sf author Hal Clement discuss possible alternative life-forms and the significance of technology in interplanetary communication. Univ. of California astrophysicist Frank Drake reappraises his own Drake Equation, a formula for estimating the number of advanced technological civilizations in the universe; several contributors describe current SETI programs; and Kent Cullers, NASA signal-detection team leader, and William Alschuler, founder of Future Museums, describe ways ordinary American citizens can productively participate in the SETI program with only $3,000 worth of equipment. Specific instructions for setting up the equipment are included in the appendices, along with a list of intriguing stars to watch. A comprehensive overview that inspires as well as informs.