Sally Mann’s hypnotic and ethereal photographs are considered monumental works of American contemporary art, held in museum collections across the world. She’s been the subject of two documentaries, a Smithsonian retrospective and 1990s cancel culture controversies. But since 2015’s publication of her first book of prose, “Hold Still,” she has also emerged as one of the finest American memoirists, a writer with a gift for language as exquisite and distinctive as her monochrome imagery. It’s almost unbelievable that one artist could possess such mastery across mediums. How, one may ask, is it even possible?