6 p.m., the theater at Cape Henlopen High School, Lewes. Bestselling author Erik Larson will discuss his latest book, "The Demon of Unrest: A Saga of Hubris, Heartbreak, and Heroism at the Dawn of the Civil War.”  Larson will be in conversation with Bryan Russo, an award-winning journalist and program director for Delmarva Public Media. Tickets are $35 plus a $2.75 processing fee. To purchase tickets, go to historybookfestival.org.