India, May 25 -- The young man who would one day rewrite humanity's understanding of black holes was, in the eyes of his own father, drifting. He wandered the family home without ambition. He did not appear to study. And he had begun to confess, with a teenager's casual cruelty toward his own gifts, that he had lost faith in physics.

It is 1961. The student in question is nineteen years old. His name is Stephen Hawking.

Newly surfaced diaries kept by Frank Hawking, the eminent tropical-disease specialist who fathered the most famous scientist of the modern era, paint a portrait of family worry that runs flatly against the polished mythology built around his son in the decades since. The notebooks, some of them written in a private code...