"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 (the full list is here):
Stephen R. Covey
In The 7 Habits of Highly Effective People, author Stephen R. Covey presents a holistic, integrated, principle-centered approach for solving personal and professional problems. With penetrating insights and pointed anecdotes, Covey reveals a step-by-step pathway for living with fairness, integrity, service, and human dignity--principles that give us the security to adapt to change and the wisdom and power to take advantage of the opportunities that change creates.