Loulou de La Falaise (1947-2011) was best known as Yves Saint Laurent’s muse, confidante, alter ego—and the virtuoso behind all his famously flamboyant accessories: towering fur toques, clanking bronze cuffs, necklaces strung with coral. Adventurousness typified not only her designs but also her approach to the art of living, in homes of distinguished pedigree in England, Ireland, France, and Italy, as I learned while researching her biography Loulou & Yves: The Untold Story of Loulou de La Falaise and the House of Saint Laurent, out this month from St. Martin’s Press.