The three books in the trilogy, which are only loosely connected, are ''Out of the Silent Planet,'' ''Perelandra,'' and ''That Hideous Strength.'' They take place on Mars, Venus, and Earth respectively. | The three books in the trilogy, which are only loosely connected, are ''Out of the Silent Planet,'' ''Perelandra,'' and ''That Hideous Strength.'' They take place on Mars, Venus, and Earth respectively. |