To Open The Sky
The Front Pages of Christopher P. Winter
The Search for Extraterrestrial Intelligence
Here are some links to relevant external sites (updated 5/15/2005).
RADIO ASTRONOMY'S ORIGINS
SOME SETI SITES
Here are some citations for books providing additional information.
There are hundreds of books on the subject of extraterrestrial life. I won't try to list even a representative sample here. But the four books I do list will give anyone unfamiliar with the literature a good start on understanding why the Great Silence is so puzzling. In addition, the first cites lots of good sources for further exploration, while the last two present conflicting and well-constructed arguments on the rarity or abundance of complex life forms.