First published in 1927, The Hardy Boys series are mystery-adventure books depicting brothers Frank and Joe's daring capers. Like the Nancy Drew series, the characters were created by Edward Stratemeyer for his book packaging company Stratemeyer Syndicate and were all ghost written under the pen name Franklin W. Dixon. The mystery series began with The Tower Treasure and has expanded to over 200 books, with the boys now featured in The Hardy Boys: Undercover Brother series.