Does he like Richard Feynman?
I love giving out this book to people because it's cute, funny, smart, and just wonderful: http://www.amazon.com/Classic-Feynman-Adventures-Curious-Character/dp/0393061329
He might have already read it though :S
Otherwise, Code Complete is a must if he hasn't read it already! :D http://www.amazon.com/Code-Complete-Practical-Handbook-Construction/dp/0735619670/ref=sr_1_1?s=books&ie=UTF8&qid=1423863414&sr=1-1&keywords=code+complete