Ace Books began its second G-series in 1964, and it ran until 1968, with serial numbers from 501 to 766.
There had previously been nine titles with a G prefix published as part of the D/G/S-series. These nine are:
The nine titles above are also listed in the D/G/S-series, but are separated here for convenience.
After the numbers in the D/G/S-series reached 500, the G series began to use separate numbers. These are the titles listed below.
Some G-series numbers are not listed, and it is not known if a book corresponds to them; the missing numbers are: 516 and 517.
Donald Allen Wollheim was an American science fiction editor, publisher, writer, and fan. As an author, he published under his own name as well as under pseudonyms, including David Grinnell, Martin Pearson, and Darrell G. Raynor. A founding member of the Futurians, he was a leading influence on science fiction development and fandom in the 20th-century United States. Ursula K. Le Guin called Wollheim "the tough, reliable editor of Ace Books, in the Late Pulpalignean Era, 1966 and '67", which is when he published her first two novels in Ace Double editions.
Charlotte Armstrong Lewi was an American writer. Under the names Charlotte Armstrong and Jo Valentine she wrote 29 novels, as well as short stories, plays, and screenplays. She also worked for The New York Times' advertising department, as a fashion reporter for Breath of the Avenue, and in an accounting firm. Additionally, she worked for the New Yorker magazine, publishing only three poems for them.