Five extraordinary stories by one of Science Fiction's most revered writers. THE TOWERS OF TITAN — Across the frozen cliffs they loomed—the unbelievably ancient towers with the unimaginable engines deep inside them still pouring out their endless power. Dr. Sidney Lee, back from living death, vowed to find the secret of the Towers of Titan! THE NEXT LOGICAL STEP — Ordinarily the military least wants to have the others know the final details of their war plans. But, logically, there would be times ... ANSWER, PLEASE ANSWER — Astronomer Bova draws upon the facts of his field to weave a story that will grip your emotions and tantalize your mind—long after you have finished reading it. THE DUELING MACHINE — The trouble with great ideas is that someone is sure to expend enormous effort and ingenuity figuring out how to louse them up. A LONG WAY BACK— He held the future of the world in his numbed hands. And from 22,500 miles out, he made the gamble.