The Rover Boys, or The Rover Boys Series for Young Americans, was a popular juvenile series written by Arthur M. Winfield, a pseudonym for Edward Stratemeyer. Thirty titles were published between 1899 and 1926 and the books remained in print for years afterward. The Rover boys' children (Fred, son of Sam Rover; Jack, son of Dick; Andy and Randy, twin sons of Tom) became the main characters of the "second series" that began with Volume 21, The Rover Boys at Colby Hall, published in 1917. The elder Rovers continued making appearances in the second series.