April 4, 1968, 6:01 p.m.: the fateful moment of the assassination of the Rev. Martin Luther King Jr. that left our country wondering, "Why?" In Hellhound on His Trail: The Stalking of Martin Luther King Jr. and the International Hunt for His Assassin, HAMPTON SIDES looks at the life of James Earl Ray, King's infamous killer, and the tragic instant the two mens' lives came together on a balcony of the Lorraine Motel in Memphis. Sides discusses the book in conjunction with the Decatur Book Festival, A Cappella Books and the Marcus Jewish Community Center of Atlanta. Free. 7 p.m. Jimmy Carter Library & Museum, 441 Freedom Parkway. 404-865-7100. www.jimmycarterlibrary.gov.