These classic adventure books were a favorite of many young readers as 2 sons of a detective solve a variety of cases. Books are written for readers 8-12. Ideal for a young family/grandkids that like to read. Have been in storage for several years since our kids grew up. Could be a great Christmas gift for that reader in the family Make me an offer, going rate seems to be $2 to $5 per book Attached is a list of the books including the revision year: # Title Rev. 1 The Tower Treasure 1959 2 The House on the Cliff 1987 3 The Secret of the Old Mill 1962 4 The Missing Chums 1990 19 The Disappearing Floor 1992 53 The Clue of the Hissing Serpent 1998