1. The art of doing science and engineering by Richard Hamming. This might be the best engineering book I've ever read. Hamming's breadth and depth are fascinating. His back of the envelope calculations are crazy accurate and early accounts of computing hilarious(real programmers write machine code). There is a great account of his discovery of error correcting codes and a great account of his failure to discover FFT. All in all it's a wonderful book on how to think about things in science and engineering.
2. The open society and its enemies by Karl Popper. This is a great book on open society and liberal democracy. Broadly the book is a critic of historicist theories of Plato and Marx. There is also good philosophy on essentialism and the futility of getting closer to the truth by defining things more precisely.
3. Printing Press as an agent of change by Elizabeth Eisenstein. This account of the impact of the printing press on Europe is very long but worth it. The parts on the scientific revolution are particularly good.