Philip K. Dick
This book can be downloaded and read in Apple Books on your Mac or iOS device.
The plot centers around protagonist Conger, a man who is given a chance to get out of jail if he agrees to do a job: traveling back in time in order to kill a man who would later prove to change the world. Congers' target is a man who appeared in 1960 in a small town in the US, and who spawned a new religious movement which radically changed the world over the next few hundred years.
Profound. A great story,that induces thinking for ages. Great concepts of Time Travel,Destiny, and Reality. I've only read it yesterday,and yet it is still on the mind.