"Who's There?" was first published in the November 1958 issue of New Worlds. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

The Sentinel was first published in the spring 1951 issue of 10 Story Fantasy. It later served as the starting point for the film and novel, 2001: A Space Odyssey. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"Time's Arrow" was first published in the summer 1950 issue of Science-Fantasy. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

June 1958 issue of If. It was later expanded into the novel of the same name. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"Before Eden" was first published in the June 1961 issue of Amazing. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most influential science fiction writers of all time. He was named a grand master by the Science Fiction and Fantasy Writers of America and was inducted into the Science Fiction and Fantasy Hall of Fame.

"The Last Command" was first published in the November 1965 issue of Bizarre! Mystery Magazine. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most influential science fiction writers of all time. He was named a grand master by the Science Fiction and Fantasy Writers of America and was inducted into the Science Fiction and Fantasy Hall of Fame.

"Hide-and-Seek" was first published in the September 1949 issue of Astounding Science-Fiction. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

Dog Star was first published in the April 1962 issue of Galaxy. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

>"Publicity Campaign" was first published in 1953 in the London Evening News. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"On Golden Seas" first appeared in the August 1986 issue of Newsletter, published by the Pentagon Defense Science Board. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"History Lesson" was first published in the May 1949 issue of Startling Stories. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"Superiority" was first published in the August 1951 issue of The Magazine of Fantasy and Science Fiction. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"'If I Forget Thee, Oh Earth...'" was first published in the September 1951 issue of Future. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

"Nightfall" was first published in 1947 in King's College Review. Sir Arthur C. Clarke (1917-2008) is regarded as one of the most-influential science fiction writers of all time. He was named a Grand Master by the Science Fiction and Fantasy Writers of America, and was inducted into the Science Fiction and Fantasy Hall of Fame.

Fleeing Earth after an alien invasion, the human race stands on the threshold of evolution. Their new home is Luna, a moon colony blessed with creature comforts, prolonged lifespans, digital memories, and instant sex changes. But the people of Luna are bored, restless, suicidal - and so is the computer that monitors their existence.