Colin Salter is a prolific author of literary history. For Batsford he has written 100 Books that Changed the World, 100 Letters that Changed the World and 100 Speeches that Roused the World. He is the author of a biography of Mark Twain and is currently working on a history of the books in one family's three-hundred-year-old library. He lives in Edinburgh with his wife, dog and bicycle. Scott Christianson (1947 2017) was a prize-winning author. His books included 100 Diagrams That Changed the World and Freeing Charles: The Epic Struggle to Free a Slave on the Eve of the Civil War. His articles have appeared in The New York Times, Washington Post, Village Voice, and Newsday.