Nicholas Day is the author of The Mona Lisa Vanishes, a middle-grade book of narrative nonfiction about the wild, improbable story of how the Mona Lisa was stolen—and how it became the most famous painting in the world. The Mona Lisa Vanishes won the Robert F. Sibert Award and the Boston Globe-Horn Book Award for nonfiction. He’s also the author of the picture book Nothing: John Cage and 4’33”, illustrated by Chris Raschka.

His next work of middle-grade narrative nonfiction, A World Without Summer: A Volcano Erupts, A Creature Awakens, and the Sun Goes Out, illustrated by Yas Imamura, will be published in September, 2025.

For adults, he’s the author of Baby Meets World, a work about the science and history of infancy, which Mary Roach called “a perfect book.”

He has written regularly for Slate; his work has also appeared in The Atlantic, The New York Times, and The Washington Post, among other publications. He lives in Western Massachusetts with his family.

Nicholas is represented by Brenda Bowen at The Book Group. He can be reached at nicholassday@gmail.com. He’s on Instagram @bynicholasday.