NEW YORK – A novel about identity and a missing youth, a history of the overthrow of the Shah of Iran and a picture book celebrating the underappreciated belly button are this year’s winners of the Kirkus Prize, which includes a $50,000 cash award for each of the three categories.

Lucas Schaefer’s “The Slip,” which follows a man’s search for a nephew who disappeared years earlier, won for fiction, while the award for nonfiction was given to Scott Anderson’s “King of Kings: The Iranian Revolution: A Story of Hubris, Delusion and Catastrophic Miscalculation.” The winner for young readers’ literature was Thao Lam’s “Everybelly,” a poolside view of belly buttons and the stories they tell.

Established in 2014, the prizes are overseen by the trade publication Kirkus Reviews.

“This year’s Kirkus Prize winners bring us vital messages for our time — messages about the joys of community, the power of self-transformation, and the mutability of historical events — all conveyed through exhilarating prose and pictures,” Kirkus Editor-in-Chief Tom Beer said in a statement Wednesday.

Finalists included Angela Flournoy’s novel “The Wilderness”; Nicholas Boggs’ biography of James Baldwin, “Baldwin: A Love Story”; and Arundhati Roy’s memoir, “Mother Mary Comes to Me.”