A couple very important ones;

Overshoot: The Ecological Basis of Revolutionary Change, by william Catton
http://www.amazon.com/Overshoot-Ecological-Basis-Revolutionary-Change/dp...

Also;

Limits to Growth: The 30-Year Update
by Donella H. Meadows (Author), Jorgen Randers (Author), Dennis L. Meadows (Author)

http://www.amazon.com/Limits-Growth-Donella-H-Meadows/dp/193149858X

I second Soup's choice of Overshoot. I have read most of the books mentioned above and perhaps 25 or 30 others on the subject. Overshoot is by far the very best of all. It was written in 1980 and that what was and is happening should be obvious to anyone with true insight.

My second choice would not be a book at all but an essay you can read in about 20 minutes,
Energy and Human Evolution by David Price. Price's essay was written in 1995. Price died in 1998.

Ron Patterson

Thanks for the link! Very interesting :-)

Souperman2,

I also second Catton's classic.

Add Georgescu-Roegen's 'The Entropy Law and the Economic Process':

http://www.amazon.com/Entropy-Law-Economic-Process/dp/1583486003