Hardy Boys Collection 13 Titles Vintage.

The clue of the broken blade 21. 1942

The secret of the old mill 3. 1962

The secret warning 17. 1966

The mystery of the spiral bridge 45. 1966

The secret panel 25. 1969

The mysterious caravan 54. 1975

While the clock ticked 11. 1962

The phantom freighter 26. 1970

The hooded hawk mystery 34. 1954

The arctic patrol mystery 48. 1969

The house on the cliff 2. 1959

The twisted claw 18. 1939

Mystery of the whale tattoo 47. 1970

3 of the books have written names on the first page, no other writing throughout.