When the artist Françoise Gilot walked out on Pablo Picasso after a long and turbulent relationship, he told her she would be nothing without him and set out to destroy her career. Gilot later recalled how her former lover told her: “You imagine people will be interested in you? They won’t ever, really, just for yourself … It will only be a kind of curiosity they will have about a person whose life touched mine so intimately.” After the split, Picasso and his influential friends in France’s artistic and intellectual circles waged what she described as a “war” on her,...