Question and Answer is a science fiction novel by American writer Poul Anderson. It originally appeared in the June and July 1954 issues of magazine Astounding Science Fiction, and was later reprinted in 1956 as part of Ace Double D-199 under the title Planet of No Return, and again as a stand-alone Ace novel in February 1978 under the original title.

Messier 13 or M13, is a globular cluster of several hundred thousand stars in the constellation of Hercules.