Robert Craft has been the keeper of the Stravinsky legacy. But it’s difficult to separate where one leaves off and the other begins. “Craft’s influence on Stravinsky was such that it was sometimes hard to tell who was responsible for what. Three decades after Stravinsky’s death in 1971, that symbiosis is starting to seem merely part of the Postmodern musical landscape. Still, Craft’s talent to be revelatory and obfuscatory at the same time makes his peculiar memoir, ‘An Improbable Life,’ as infuriating as it is engrossing.”