Hardy Boys 27: The Secret of Skull Mountain Other Books in This Series
Hardy Boys 28: The Sign of the Crooked Arrow
1949
Hardy Boys 29: The Secret of the Lost Tunnel
1950
Hardy Boys 31: The Secret of Wildcat Swamp
1952
Hardy Boys 32: The Crisscross Shadow
1953
Hardy Boys 33: The Yellow Feather Mystery
1954
Hardy Boys 34: The Hooded Hawk Mystery
1955
Hardy Boys 35: The Clue in the Embers
1956
Hardy Boys 36: The Secret of Pirates' Hill
1957
Hardy Boys 37: The Ghost at Skeleton Rock
1958
Hardy Boys 38: Mystery at Devil's Paw
1959
Hardy Boys 39: The Mystery of the Chinese Junk
1959
Hardy Boys 40: Mystery of the Desert Giant
1960
Hardy Boys 41: The Clue of the Screeching Owl
1962
Hardy Boys 42: The Viking Symbol Mystery
1962
Hardy Boys 43: The Mystery of the Aztec Warrior
1964