Mr. Kennedy said that his father had encouraged intensive competition among his children, especially his sons, which fed his recurrent feelings of inadequacy after the death of his three brothers, all of them older.

“Competition, of course, is the route to achievement in America,” Mr. Kennedy wrote. “As I think back to my three brothers, and about what they had accomplished before I was even out of my childhood, it sometimes has occurred to me that my entire life has been a constant state of catching up.”