Is there life on other worlds? Nobody knows--but the search, as recounted here, has been vastly entertaining. Ever since Galileo showed the planets to be other worlds, it has been apparent that some of them must harbor life. But despite nearly four centuries of searching, definitive proof of this widely accepted postulate remains elusive. A father-son team made up of a cosmochemistry professor (David, at the Univ. of Miami) and a popular-science writer (Marshall, author of Tube, 1996), the Fishers chronicle the history of this search, and speculate on its eventual conclusion. The first half of the book focuses on our nearest planetary neighbor, Mars. A brief history of the philosophical and scientific underpinnings of the belief that life exists beyond our world leads up to Percival Lowell, who toward the end of the 19th century argued fervently that the Martian ""canals"" (since proven to be optical illusions) were evidence of intelligent life. These arguments fell on fertile ground, at least among the general population. Marconi and Tesla both claimed to have gotten signals from Mars via the newly invented radio, but attempts to duplicate their results never panned out. Reluctantly, as more and better data accumulated, scientists decided that Mars was in fact a dead world--although there may be fossils in a meteor believed to be of Martian origin. The search has moved to other worlds--for example, to the moons of Jupiter, some of which may have oceans. Radio telescopes allow the search to examine other galaxies, although results to date are inconclusive. A final chapter looks at the implications of actually finding life: not only what it will mean to science, but how ordinary people are likely to respond. The Fishers present their history interestingly, touch on all the relevant science, and provide plenty of food for thought. A readable and comprehensive overview of this fascinating quest.