The link below tells about Galileo's book "laying out the arguments in favor of the heliocentric theory" (dsm.fordham.edu).
http://www.dsm.fordham.edu/~moniot/galileo_from_a_different_angle/node6.html

This is just one of the few books Galileo wrote in his life. Like the others, he wrote about different science philosophies and beliefs trying to prove different points and theories.