Mother-son team Jonah and Jeanette Winter bring to life one of the most secretive scientific projects in history--the creation of the atomic bomb--in this "astonishing...beautifully told" (Kirkus Reviews, starred review) picture book.

At a former boy's school in the remote desert of New Mexico, the world's greatest scientists have gathered to work on the "Gadget," an invention so dangerous and classified they cannot even call it by its real name. They work hard, surrounded by top security and sworn to secrecy, until finally they take their creation far out into the desert to test it, and afterward the world will never be the same.