Interest in extrasolar worlds is not new. From the late 17th century until the end of the 19th, almost all educated people believed that the stars are suns surrounded by inhabited planets—a belief that was expressed not in science fiction, but in serious speculation, both scientific and religious, as well as in poetry. Only during the first half of the 20th century was it thought that life-bearing extrasolar planets are rare.

This book, first published by Atheneum in 1974, tells the story of the rise, fall, and eventual renewal of widespread conviction that we are not alone in the universe. Its chapters dealing with modern views have been revised to reflect the progress science has made during the past 40 years, including the actual detection of planets orbiting other stars.

In addition it has a new Appendix containing passages from early poetry mentioning extrasolar worlds, and a long Afterword, "Confronting the Universe in the Twenty-First Century," discussing the relevance of past upheavals in human thought to an understanding of the hiatus in space exploration that has followed the Apollo moon landings. (A slightly modified version appears in The Space Review.)

"Engdahl has marshalled an impressive and fascinating selection of primary sources. . . . [She] has shown how deep this vein of speculation runs . . . and reminded us that our ancestors entertained a view of the universe that was larger and more imaginative than the history books lead us to believe. Challenging and original." —Kirkus Reviews