Science Fiction: http://news.ycombinator.com/item?id=2978027
Computer Science: http://news.ycombinator.com/item?id=3595599
General: http://news.ycombinator.com/item?id=1752139
Design: http://news.ycombinator.com/item?id=3276986
Computer Science: http://news.ycombinator.com/item?id=1636275
Developing mental models and increasing cognition: http://news.ycombinator.com/item?id=3277457
Quant finance: http://news.ycombinator.com/item?id=3177815
General: http://news.ycombinator.com/item?id=663662
General (non software): http://news.ycombinator.com/item?id=1226736
Math: http://news.ycombinator.com/item?id=665029
General: http://news.ycombinator.com/item?id=875686
Entrepreneur: http://news.ycombinator.com/item?id=2928211
Statistics: http://news.ycombinator.com/item?id=902074
Philosophy: http://news.ycombinator.com/item?id=1503137
General: http://news.ycombinator.com/item?id=1865350
Math for beginners: http://news.ycombinator.com/item?id=755043
Military strategy: http://news.ycombinator.com/item?id=456275
General: http://news.ycombinator.com/item?id=797070
Investing: http://news.ycombinator.com/item?id=248469
"I want to start a web company": http://news.ycombinator.com/item?id=1567456
As a broke fresh college graduate, one of the most widely talked about books (and one I actually bought myself) was Eric Ries' The Lean Startup. It really helped me feel like I had a sense of direction instead of "thinking I knew" something,
Even if a book you want isn't in the library's catalog, go talk to a librarian. They can work some magic.
Another thing to do is see if your college will let you keep online or other library access for a nominal fee. I remember (ab)using MIT libraries for a while after leaving.