Sly Stone, who invented his personal sort of funky hybrid of rock ‘n’ roll and R&B together with his ’60s group Sly and the Household Stone, has been dwelling a personal life for many years. Now 80, the reclusive music nice has simply penned a memoir, “Thank You (Falettinme Be Mice Elf Agin).” Correspondent Kelefa Sanneh talks with Questlove (who printed the e-book), Sly’s longtime buddy George Clinton, and with Sly’s actual household, concerning the musician’s revolutionary band; a life revolving round medication; and the way he’s right this moment.