The Three Investigators Series List of Titles

The Three Investigators series consists of 43 titles.  The series was created by Robert Arthur and was intended to be better than series books like the Hardy Boys.  He wrote 10 books until his failing health and subsequent death ended his involvement in the series.

#1-28 were published in hardcover trade editions.  #29-43 were published in softcover editions.  #29-43 were made available in hardcover library editions to libraries, and those books are extremely hard to find and usually surface in poor condition.  This series has been largely unaffected by the huge drop in series book prices that began in 2008.  These books still sell for very strong prices, including most of the lower-numbered titles and especially the higher-numbered titles. 

  1. The Secret of Terror Castle, 1964, Robert Arthur
  2. The Mystery of the Stuttering Parrot, 1964, Robert Arthur
  3. The Mystery of the Whispering Mummy, 1965, Robert Arthur
  4. The Mystery of the Green Ghost, 1965, Robert Arthur
  5. The Mystery of the Vanishing Treasure, 1966, Robert Arthur
  6. The Secret of Skeleton Island, 1966, Robert Arthur
  7. The Mystery of the Fiery Eye, 1967, Robert Arthur
  8. The Mystery of the Silver Spider, 1967, Robert Arthur
  9. The Mystery of the Screaming Clock, 1968, Robert Arthur
10.  The Mystery of the Moaning Cave, 1968, William Arden (Dennis Lynds)
11.  The Mystery of the Talking Skull, 1969, Robert Arthur
12.  The Mystery of the Laughing Shadow, 1969, William Arden (Dennis Lynds)
13.  The Secret of the Crooked Cat, 1970, William Arden (Dennis Lynds)
14.  The Mystery of the Coughing Dragon, 1970, Nick West (Kin Platt)
15.  The Mystery of the Flaming Footprints, 1971, M. V. Carey (Mary Virginia Carey)
16.  The Mystery of the Nervous Lion, 1971, Nick West (Kin Platt)
17.  The Mystery of the Singing Serpent, 1972, M. V. Carey (Mary Virginia Carey)
18.  The Mystery of the Shrinking House, 1972, William Arden (Dennis Lynds)
19.  The Secret of Phantom Lake, 1973, William Arden (Dennis Lynds)
20.  The Mystery of Monster Mountain, 1973, M. V. Carey (Mary Virginia Carey)
21.  The Secret of the Haunted Mirror, 1974, M. V. Carey (Mary Virginia Carey)
22.  The Mystery of the Dead Man's Riddle, 1974, William Arden (Dennis Lynds)
23.  The Mystery of the Invisible Dog, 1975, M. V. Carey (Mary Virginia Carey)
24.  The Mystery of Death Trap Mine, 1976, M. V. Carey (Mary Virginia Carey)
25.  The Mystery of the Dancing Devil, 1976, William Arden (Dennis Lynds)
26.  The Mystery of the Headless Horse, 1977, William Arden (Dennis Lynds)
27.  The Mystery of the Magic Circle, 1978, M. V. Carey (Mary Virginia Carey)
28.  The Mystery of the Deadly Double, 1978, William Arden (Dennis Lynds)
29.  The Mystery of the Sinister Scarecrow, 1979, M. V. Carey (Mary Virginia Carey)
30.  The Secret of Shark Reef, 1979, William Arden (Dennis Lynds)
31.  The Mystery of the Scar-Faced Beggar, 1981, M. V. Carey (Mary Virginia Carey)
32.  The Mystery of the Blazing Cliffs, 1981, M. V. Carey (Mary Virginia Carey)
33.  The Mystery of the Purple Pirate, 1982, William Arden (Dennis Lynds)
34.  The Mystery of the Wandering Cave Man, 1982, M. V. Carey (Mary Virginia Carey)
35.  The Mystery of the Kidnapped Whale, 1983, Marc Brandel (Marcus Breresford)
36.  The Mystery of the Missing Mermaid, 1983, M. V. Carey (Mary Virginia Carey)
37.  The Mystery of the Two-Toed Pigeon, 1984, Marc Brandel (Marcus Breresford)
38.  The Mystery of the Smashing Glass, 1984, William Arden (Dennis Lynds)
39.  The Mystery of the Trail of Terror, 1984, M. V. Carey (Mary Virginia Carey)
40.  The Mystery of the Rogues' Reunion, 1985, Marc Brandel (Marcus Breresford)
41.  The Mystery of the Creep-Show Crooks, 1985, M. V. Carey (Mary Virginia Carey)
42.  The Mystery of Wreckers' Rock, 1986, William Arden (Dennis Lynds)
43.  The Mystery of the Cranky Collector, 1987, M. V. Carey (Mary Virginia Carey)

If you are interested in learning more about this series, please visit these sites.

The Three Investigators U.S. Editions Collector Site 
The Three Investigators
Three Investigators: Green Gate One