Physician Bess Codman has returned to her family's Nantucket compound, Cliff House, for the first time in four years. Her great-grandparents built Cliff House almost a century before, but due to erosion, the once-grand home will soon fall into the sea. Though she's purposefully avoided the island, Bess must now pack up the house and deal with her mother, a notorious town rabble- rouser, who refuses to leave. The Book of Summer unravels the power and secrets of Cliff House as told through the voices of Ruby Packard, a bright-eyed and idealistic newlywed on the eve of WWII, the home's definitive guestbook, and Bess herself. Bess's grandmother always said it was a house of women, and by the very last day of the very last summer at Cliff House, Bess will understand the truth of her grandmother's words in ways she never contemplated.