"What is the book that changed your life? (not novels or religious texts)"
I think it's a wonderful way to connect in a less superficial way and learn a little more about each other. It's also a wonderful way to discover new books worth reading.
This is one of them:
Unix Network Programming
W. Richard Stevens
Written for programmers using a UNIX…<194> operating system, this guidebook develops the basic framework of a UNIX process, including how they are created and how they interact with an operating system.