After tracking down incredible discoveries by Einstein and Darwin, Charlie is back. This time, the great ruler Cleopatra has left behind an extremely valuable a

“Fast-paced, smart, and action-packed...a real page-burner.” —Chris Grabenstein, #1 New York Times bestselling author of the Mr. Lemoncello’s Library se

In this sequel to the New York Times bestselling Charlie Thorne and the Last Equation—which #1 New York Times bestselling author Chris Grabenstein called “a

Loyalty is tested in this second book in the thrilling time travel adventure trilogy from New York Times bestselling Charlie Thorne and Spy School author Stuart

In 2041 on Moon Base Alpha, thirteen-year-old Dash must solve the mystery of how Lars was poisoned before the base loses oxygen, forcing the colonists to return