"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:
Jared Diamond puts the case that geography and biogeography, not race, moulded the contrasting fates of Europeans, Asians, Native Americans, sub-Saharan Africans, and aboriginal Australians. An ambitious synthesis of history, biology, ecology and linguistics, Guns, Germs and Steel is a ground-breaking and humane work of popular science that can provide expert insight into our modern world.