"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):
Inspired by the remarkable surviving letters of Galileo's eldest child, the cloistered nun Suor Maria Celeste, this compelling biography of the man Albert Einstein called ‘the father of modern physics—indeed of modern science altogether’ is unlike any other. Dava Sobel dramatically revives the personality and accomplishment of a mythic figure whose seventeenth-century clash with Catholic doctrine continues to define the schism between science and religion. Moving between Galileo's grand public life and Maria Celeste's sequestered world, Sobel illuminates the Florence of the Medicis and the papal court in Rome during the pivotal era when humanity's perception of its place in the cosmos was being overturned and when one man sought to reconcile the Heaven he revered as a good Catholic with the heavens he revealed through his telescope.