Preface from Unicorn Variations: This story came into being in asomewhat atypical fashion. The first movement in its directionoccurred when Gardner Dozois phoned me one evening and asked whetherI'd ever done a short story involving a unicorn. I said that I hadnot. He explained then that he and Jack Dann were putting together areprint anthology of unicorn stories, and he suggested that I writeone and sell it somewhere and then sell them reprint rights to it.Two sales. Nice. I told him that I'd think about it.

Later, I was asked by another anthologist whether I'd ever done astory set in a barroom—and if so, he's like it for a reprintcollection he was doing. I allowed that I hadn't. A week or so afterthat, I attended a wine tasting with the redoubtable George R. R.Martin, and during the course of the evening I decided to mention theprospective collections in case he had ever done a unicorn story or abarroom story. He hadn't either, but he reminded me that FredSaberhagen was putting together a reprint collection of storiesinvolving chess games (_Pawn to Infinity_). "Why don't you," he said,"write a story involving a unicorn and a chess games, set it in abarroom and sell it to everybody?" We chuckled and sipped. A fewmonths later, I went up to Vancouver, B.C., to be the guest of V-Con,a very pleasant regional science fiction convention. I had decided totake my family on the Inland Passage Alaskan cruise after that. Nowright before I left New Mexico I had read Italo Calvino's _InvisibleCities_, and when I read the section titled "Hidden Cities. 4."something seemed to stir. It told of the city where the inhabitantsexterminated all of the vermin, completely sanitizing the place, onlyto be haunted then by visions of creatures that did not exist. Later,during the convention, things began to flow together; and on my way