Stuart Gibbs is the New York Times bestselling author of the Charlie Thorne series, the FunJungle series, Moon Base Alpha series, and Spy School series. He has written screenplays, worked on a whole bunch of animated films, developed TV shows, been a newspaper columnist, and researched capybaras (the world’s largest rodents). Stuart lives with his family in Los Angeles. You can learn more about what he’s up to at StuartGibbs.com.

William Alexander won the National Book Award for his debut novel, Goblin Secrets, and won the Earphones Award for his narration of the audiobook. His other novels include A Festival of Ghosts, A Properly Unhaunted Place, Ghoulish Song, Nomad, and Ambassador. William studied theater and folklore at Oberlin College, English at the University of Vermont, and creative writing at the Clarion workshop. He teaches in the Vermont College of Fine Arts MFA program in Writing for Children and Young Adults. Like the protagonist of Nomad and Ambassador, William is the son of a Latino immigrant to the US. Visit him online at WillAlex.net and GoblinSecrets.com, and on Twitter via @WillieAlex.

Ken Jennings grew up in Seoul, South Korea, where he became a daily devotee of the quiz show Jeopardy! In 2004, he successfully auditioned for a spot on the show and went on an unprecedented seventy-four game victory streak worth $2.52 million. Jennings’s book Brainiac, about his Jeopardy! adventures, was a critically acclaimed New York Times bestseller, as were his follow-up books Maphead and Because I Said So! He is also the author of Planet Funny. Jennings lives in Seattle with his wife Mindy and two children.

Wesley King is the author of the Edgar Award–winning OCDaniel, which Booklist praised as “complex and satisfying” in a starred review. It was named a Bank Street Best Book of the Year and received Canada’s Silver Birch Award. Its companion, Sara and the Search for Normal, received a starred review from School Library Journal.  King’s first middle grade novel, The Incredible Space Raiders from Space!, was called “a well-drafted coming-of-age story” by Publishers Weekly. King is also the author of Kobe Bryant’s New York Times bestselling Wizenard series. He lives in Nova Scotia.

Mark Kelly is a retired astronaut and US Navy Captain. His picture book Mousetronaut, illustrated by C. F. Payne was a #1 New York Times bestseller. He flew his first of four missions in 2001 aboard Space Shuttle Endeavour, the same space shuttle that he commanded on its final flight in May 2011. In 2020 he will be running to represent Arizona in the United States Senate.