The Galactic Empire series (also called the Empire novels or trilogy) is a science fiction sequence of three of Isaac Asimov's earliest novels, and extended by one short story. They are connected by their early place in his published works and chronological placement within his overarching Foundation Universe, set around the rise of Asimov's Galactic Empire, between the Robot and Foundation series to which they were linked in Asimov's later novels.
In order of internal chronology the Empire series consists of:
(Although, it is to be noted that Asimov stated in 1988 in the "Author's Note" to Prelude to Foundation that book #6 was "The Currents of Space" (1952) and that this was "the first of my Empire novels" and that book #7 was "The Stars, Like Dust" (1951), which was "The second Empire novel".)
The three Empire books, first published between 1950 and 1952, are Asimov's three earliest novels published in his own name (David Starr, Space Ranger was published before The Currents of Space, but had been published under his pen name "Paul French", and the Foundation books were collections of linked short stories rather than continuous novels).
Pebble in the Sky was originally written in the summer of 1947 under the title "Grow Old with Me" for Startling Stories, whose editor Sam Merwin, Jr. had approached Asimov to write a forty thousand word short novel for the magazine. The title was a misquotation of Robert Browning's Rabbi ben Ezra, the first few lines of which (starting "Grow old along with me! / The best is yet to be...") were included in the final novel. It was rejected by Startling Stories on the basis that the magazine's emphasis was more on adventure than science-heavy fiction (despite the editor inviting Asimov to write the latter as an experiment for the magazine), and again by John W. Campbell, Asimov's usual editor. In 1949, Doubleday editor Walter I. Bradbury accepted the story on the suggestion of Frederik Pohl, on the condition it was expanded to seventy thousand words and the title changed to something more science fiction oriented; it was published in January 1950 as Pebble in the Sky. "Grow Old With Me" was later published in its original form along with other draft stories in The Alternate Asimovs in 1986.