I have long been interested in how mathematicians came to their ideas. I therefore read quite a few books about mathematical thoughts and mathematicians. You can find the notes that I have written for the following books:

1. George Polya-How to Solve it.pdf
2. Morris Kline-Mathematical Thought from Ancient to Modern Times I.pdf
3. Morris Kline-Mathematical Thought from Ancient to Modern Times II.pdf
4. George Polya-Mathematics and Plausible Reasoning I.pdf

Comments, criticisms, suggestions, questions are most welcome! Please send yours to wujie[at]stanford.edu