The author is Alexandra Styron, daughter of William, who is portrayed as manic depressive. I found this memoir compelling, and it has been making many “best of” lists. Here is one excerpt:
By all accounts, my sister was a cheerful baby, smart and pretty, with an easy manner. In short, an ideal firstborn. Daddy was enthralled. “Take a lesson from me and don’t get too interested in the child,” Irwin Shaw wrote in a congratulatory letter. “Since Adam’s first birthday, I’ve barely written a word, as it is much more interesting to watch all the subtle and terrible currents that run through a complex human being than to sit at a typewriter and battle with the comparatively flat and lifeless material of art. Dole the child out to yourself in small doses, for your career’s sake.”
You can buy it here.