Celebrate Paperback Book Day. Fun facts about paperback books. ✅The first paperback books were introduced in the early 19th century, but they became more popular in the mid-20th century with the emergence of mass-market paperbacks. ✅The first best-selling paperback book is often attributed to “Gone with the Wind” by Margaret Mitchell. First published in 1936, it became an instant hit and remained on the bestseller list for several years. ✅The paperback book that holds the record for the most sol