The Hardy Boys Casefiles is a young adult novel series, produced, for Simon & Schuster, by Mega-Books of New York, Inc. (later just Mega-Books) and published by Archway Paperbacks (an imprint of Simon & Schuster), between 1987 and 1998. The series lasted 127 novels, including two trilogies, making it the second longest Hardy Boys novel series, behind only the 190 volume Original series.