In 1975, the year Alison Glass turned 13, life was complicated. She had severe scoliosis. Her parents were growing apart. Her best pal, Kate Hamilton, was dealing with her own dark problems. Alternating between the adult Alison’s recollections of that year and a historical-fiction story that the girls coauthored for school, History Lesson for Girls is an ambitious but ultimately uneven look at friendship and personal history. Though Aurelie Sheehan’s writing is often bull’s-eye perfect, as when Alison’s father wears ”the scowl of love,” it can also turn completely flat. But the book’s biggest shortcoming is that the characters feel too remote, as if blurred by a 1970s soft lens.