Alfred Hitchcock: The Three Investigators - Front cover from the ''The Three Investigators'' series.The Mystery of the Talking Skull (1969) - Front cover of ''The Mystery of the Talking Skull''.The Mystery of the Invisible Dog (1975) - Front cover of ''The Mystery of the Invisible Dog''.The Secret of Skeleton Island (1966) - Front cover of ''The Secret of Skeleton Island''.The Mystery of the Headless Horse (1977) - Front cover of ''The Mystery of the Headless Horse''.The Mystery of the Nervous Lion (1971) - Front cover of ''The Mystery of the Nervous Lion''.The Secret of the Phantom Lake (1973) - Front cover of ''The Secret of the Phantom Lake''.The Secret of the Haunted Mirror (1974) - Front cover of ''The Secret of the Haunted Mirror''.The Mystery of the Vanishing Treasure (1966) - Front cover of ''The Mystery of the Vanishing Treasure''.The Mystery of the Stuttering Parrot (1964) - Front cover of ''The Mystery of the Stuttering Parrot''.The Mystery of the Shrinking House (1972) - Front cover of ''The Mystery of the Shrinking House''.The Mystery of the Stuttering Parrot (1964) - Front cover of ''The Mystery of the Stuttering Parrot''.The Mystery of the Dancing Devil (1976) - Front cover of ''The Mystery of the Dancing Devil''.The Mystery of the Silver Spider (1967) - Front cover of ''The Mystery of the Silver Spider''.The Secret of the Haunted Mirror (1974) - Front cover of ''The Secret of the Haunted Mirror''.