The article was written by the man's psychiatrist, Robert Lindner, and appeared in Harper's in 1954. (It was also a chapter in Linder's entertaining case-history book The Fifty-Minute Hour). The physicist, "Kirk Allen" (his name was changed by Lindner), worked in a government research lab, and his superiors were concerned by his behavior (Allen would often space out at work while his fantastical reveries played out in his head) so they sent him to Lindner.
I don't want to spoil the story (and the excerpt below won't spoil it). You can read it in its entirety at Harper's website (Part I, Part II). Harper's kindly opened access to the article at my request, so now anyone can read it for free. (If you subscribe to Harper's for just $16.97 in the United States and CAN$24.00 in Canada, you'll get access to all the archives dating back to 1850!)
Kirk read the numerous volumes of his “biography” over and over again. Soon he no longer needed the books “to refresh my memory,” but was able to recapitulate them entirely in his mind. While his corporeal body was living the life of a mundane boy, the vital part of him was far off on another planet, courting beautiful princesses, governing provinces, warring with strange enemies. Now, using his “biographer’s” material as a base, he took off on his own. Assisted by the maps, charts, diagrams, architectural layouts, genealogical schemes, and timetables he had painstakingly worked out while using the books for his guide, he filled in spaces between the volumes with fantasy “recollections” of his own; and when this was done, he began the task of his life: that of picking up where his “biographer” had left off and recording the subsequent history of the heroic Kirk Allen.Speculation abounds on the true identity of Kirk Allen. Alan C. Elms thinks it could be Cordwainer Smith. It's more fun for me to think Kirk Allen's real name was John Carter and that he had fantasized that being on Barsoom, fighting the bad Martians while Deja Thoris stayed at home hatching the eggs containing his and her children.
For many days I pondered the question of how Kirk Allen could be restored to sanity–and yet remain alive. For there seemed to be nothing that could compete with the unending gratifications of his fantasy. Meanwhile Kirk turned over to me all of his records.
It is impossible to convey more than a bare impression of these. There were, to begin with, about 12,000 pages of typescript comprising the amended “biography” of Kirk Allen. This was divided into some 200 chapters and read like fiction. Appended to these pages were approximately 2,000 more of notes in Kirk’s handwriting, containing corrections necessitated by his more recent “researches,” and a huge bundle of scraps and jottings on envelopes, receipted bills, laundry slips.
There also were a glossary of names and terms that ran to more than 100 pages; 82 full-color maps carefully drawn to scale, 23 of planetary bodies in four projections, 31 of land masses on these planets, 14 labeled “Kirk Allen’s Expedition to –,” the remainder of cities on the various planets; 161 architectural sketches and elevations, all carefully scaled and annotated; 12 genealogical tables; an 18-page description of the galactic system in which Kirk Allen’s home planet was contained, with four astronomical charts, one for each of the seasons, and nine star-maps of the skies from observatories on other planets in the system; a 200-page history of the empire Kirk Allen ruled, with a three-page table of dates and names of battles or outstanding historical events; a series of 44 folders containing from 2 to 20 pages apiece, each dealing with some aspect–social, economic, or scientific–of the planet over which Kirk Allen ruled. Finally, there were 306 drawings of people, animals, plants, insects, weapons, utensils, machines, articles of clothing, vehicles, instruments, and furniture.
The reader can imagine my dismay at the sheer bulk of this material; I do not know if he can appreciate with what misgivings I approached the task of weaning this man from his madness. Aside from everything else, he was my patient under the most inauspicious possible conditions, for he had not come of his own volition. The authorities had sent him, demanding he be treated not only for his sake but because they feared that in his disturbed condition he was a poor security risk who could neither be kept on the job nor discharged.