When Tony, Morrey and Serge were summoned by Sir Billy Gillanders to the U.N.E.X.A. headquarters they hoped they were to be sent on yet another mission to some distant planet. Instead they learned that they were to go to the moon, not as astronauts, but as detectives. Sir Billy wanted them to investigate a series of mysterious disappearances fro, Lunar City...

Science Fiction and Fantasy Literature, A Checklist, 1700-1974, Volume one of Two, contains an Author Index, Title Index, Series Index, Awards Index, and the Ace and Belmont Doubles Index.

Presents articles on the science fiction genre of literature, including authors, themes, significant works, and awards.

If the ladder hadn't slipped when Chris Godfrey was chalking up the sports results - and if Sir George Benson hadn't been passing at that very moment - it might never have happened. It had become imperative to fire a conscious human being into space and Sir George, who was Director of Research at Woomera, couldn't see how it was to be done until he met Chris. Once Chris agreed, things moved fast. Whisked to London by the R.A.F., he started his training, was fitted for a G-suit, got to know the landscape of the Moon as well as he knew the school sports ground. Then on to Woomera; and, at last, into space...

The four intrepid astronauts, headed by Chris Godfrey, look forward with enthusiasm to their trip to Mercury until the new crew member turns out to be a girl! Gail Patrick is being sent along to test mental telepathy as a means of communication. Her twin sister, Gill, will remain in the control room on earth to receive and send messages into space.

Chris Godfrey and his crew employ a new hypothermia technique which freezes them into unconsciousness for most of the journey, but when their ship's automatic transmitter contact with Earth ceases, the conclusion is that the expedition has met with disaster.

An expedition to Mars is decided on and Chris, Serge, Morrey and Tony are chosen to man it. Unlike their expedition to Venus, this is not a desperate last-minute venture; it is a sober, carefully planned affair. Chris and his friends have no reason to expect anything beyond the normal risks of space travel - except for the experiences of the Dutchman Van der Veen. He is the only man who has ever penetrated beyond the Le Prince layer, which blots out radio communication with the earth - and he returned in a state of mental collapse. When he hears of the new expedition he has another breakdown, and when at last he is able to describe his experiences he speaks of strange and terrifying voices that assailed him in outer space. Will Chris and his friends also here these voices, and what will they find on Mars?