Troas
Anderson was approached in 1953 by Twaine Press editor Fletcher Pratt with a story proposal: a scientist would create a world, and then he, Isaac Asimov and James Blish (Asimov thought the third writer might have been Blish's then-wife, Virginia Kidd) would write novellas set in that world. The three novellas would then be published as a book, together with an essay by the scientist who created the scenario. This formula, which Pratt called a Twaine Triplet, had already resulted in the 1952 book The Petrified Planet.
The scenario created was that of a binary star system in the Messier 13 globular cluster with an Earthlike planet called Troas (or more informally, Junior) located at one of the system's Lagrangian points. An earlier expedition to Troas had suffered some mysterious disaster, and a second expedition was being mounted to determine if the planet was suitable for colonization, and to find out what happened to the first expedition.
Anderson finished his story, and Asimov finished a story called "Sucker Bait", but Blish (or Kidd) never completed the third story, and the proposed book never saw print. Anderson was able to sell Question and Answer to Astounding (where it appeared a few months after "Sucker Bait") and later to Ace Books.
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