The book was published in 1933. It only became popular after Hilton's next book, "Goodbye, Mr. Chips", was published in 1934. "Lost Horizon" then became a huge success. In 1939, it was published in paperback, as Pocket Book #1. Because of its number-one position in what became a very long list of pocket editions, "Lost Horizon" is often called the first American paperback book. This is not correct. The first pocket-sized, paperback book sold in many stores in America was Pearl Buck's "The Good Earth" by Pocket Books in 1938 as an experiment.