I mentioned the brilliant Cordwainer Smith a while back. I forgot, however, to mention a strange aside that perhaps relates to him.
In 1995, the psychiatrist Robert Mitchell Lindner published The Fifty-Minute Hour and Other True Psychoanalytic Tales, a set of fictionalised case studies designed to showcase what happened in psychoanalysis. One of the studies, The Jet-Propelled Couch, concerned a research physicist, "Kirk Allen", who believed that he was literally transported part-time to a far-future universe where he was lord of a planet. There's a persistent story in SF circles that "Kirk Allen" was Cordwainer Smith (that is, the author and diplomat Paul C Linebarger).
Behind the Jet-Propelled Couch: Cordwainer Smith & Kirk Allen (Alan C Elms, orig. in New York Review of Science Fiction, May 2002] collates what's known of the story (where it started, the evidence, and so on). Elms is a respected biographer of Smith's work, and thinks it's quite likely. There's further comment at Was Paul Linebarger Also Kirk Allen? from Linebarger's daughter, who runs his official website; the idea is evidently not so outrageous to be beneath discussion (Linebarger was under analysis, in the right time and place). However, she does cite an article "In Search of Kirk Allen" (Lee Weinstein, New York Review of Science Fiction, April 2001) that demonstrates for a different case study "that Lindner fictionalized the stories far more than you might think". Still, she finds "interesting parallels" with Linebarger's life.
The Jet-Propelled Couch itself is available in the Harper's Magazine archive Dec 1954 / Jan 1995: subscription only, but much of it is accessible in the Google Books preview of The Fifty-Minute Hour.