A word on Immanuel Velikovsky
I don't know if people still take an interest in these theories today, but back in the sixties and seventies they got quite a lot of attention. Velikovsky's most famous book was Worlds in Collision, first published in 1950. His basic thesis is that cataclysmic events of celestial origin have had a distinct impact on ancient history.
A lengthy discussion of Velikovsky and his theories can be found in Broca's Brain by Carl Sagan (1974), chapter 7, Venus and Dr. Velikovsky.
Hey! that was a link to a non-webbed source. Is that still allowed?
There are, of course, hundreds of references to Velikovsky on the web. A quick AltaVista search will bring them up. A couple that look interesting are:
http://www.knowledge.co.uk/xxx/cat/velikovsky.htm
http://marlowe.wimsey.com/~rshand/streams/thera/velikov.html