The senior science writer for Time summarizes current scientific evidence for the presence of life beyond Earth. Lemonick (The Light at the Edge of the Universe, 1993) begins with three brief portraits of scientists engaged in various research projects: the detection of planets around other stars, the chemical analysis of a Martian meteorite, and SETI (Search for Extra-Terrestrial Intelligence) itself. These ""snapshots"" of working scientists humanize Lemonick's subject, allowing him very effectively to present technical material without losing the reader. This is very much an asset, for much of the material is not only technical but comparatively familiar. We learn again of Giordano Bruno's espousal of multiple life-bearing worlds, for which the Church burned him at the stake; of the Greek philosophers on whom Bruno drew; of the astronomical revolution led by Copernicus and Galileo. The ""Drake equation,"" which attempts to quantify the possibility of life and of advanced civilizations elsewhere in the universe, is clearly explained, as are the various (still mostly speculative) factors on which its solution is contingent. The current view of the planets of own solar system makes most of them look increasingly inhospitable to life (despite possible life traces in that Martian meteor). But around the end of WWII it became clear that planet formation was probably a more common event than had been previously believed. That set off attempts to find such planets. One series of careful observations involving nearby Barnard's Star apparently suggested planetary companions; alas, the data turned out to be an artifact of the astronomer's equipment. But more sophisticated equipment and techniques have in the last few years identified planets around several other stars in our galaxy. This gives the tree believers in SETI hopes that the elusive signal from E.T. may yet come. A vivid, clearly written account of cutting-edge science that should appeal to general audiences.