Faglitteratur
* *En psykisk detektivs eventyr* (1971)
* *Adventures in Psychical Research* (1975)
* *Mysteriet om psykisk helbredelse* (1977)
* *The Psi Factor:A Look at the Evidence for Psychic Phenomena* (1978)
* *The Loch Ness Monster:The Evidence* (1979)
* *The Mystery of the Bermuda Triangle* (1979)
* *The Poltergeist Phenomenon* (1979)
* *The Search for Atlantis* (1979)
* *The UFO Mystery:A Look at the Evidence* (1981)
* *Verdens største UFO-mysterier* (1981)
* *The Book of Psychic Phenomena* (1982)
* *The Handbook of Psychic Phenomena* (1983)
* *The Encyclopedia of Psychic Phenomena* (1984)
Fiktion
* *The Darkening of the Sun* (1957)
* *Det brændende glas* (1958)
* *The Devil's Tide* (1959)
* *Den sorte død* (1960)
* *Den store pest* (1961)
* *Sodomas og Gomorras sidste dage* (1962)
* *Pagtens Ark* (1963)
* *Tutankhamons forbandelse* (1964)
* *The Secret of Atlantis* (1965)
* *Den dag jorden stod stille* (1966)
* *Verdernes krig* (1967)
* *Tidsmaskinen* (1968)
* *20.000 ligaer under havet* (1969)
* *Rejsen til jordens centrum* (1970)
* *The Return of Sherlock Holmes* (1971)
* *The Hound of the Baskervilles* (1972)
* *Frygtens dal* (1973)
* *De fires tegn* (1974)
* *The Scarlet Thread* (1975)
* *The Last Adventure of Sherlock Holmes* (1976)
Poesi
* *Til det ukendte* (1960)
* *Havets stemme* (1962)
* *Stjernernes sange* (1964)
* *The Echoes of Eternity* (1966)
* *Vindens hvisken* (1970)
* *The Music of the Spheres* (1972)