The first book I worked on that appeared with my name on it! (Although Rose gave me occasional thanks in some of the TSR books I helped her write).
Around the time of New Infinities Productions, Bill Fawcett had obtained permission to do a pick your own adventure type book, set in the world of Fletcher Pratt & L. Sprague De Camp's Incompleat Enchanter Series (I grew up loving Harold Shea and Belphebe). He offered me the job, and I jumped at the chance. The story took almost half a year to complete on an old Apple IIe (working at night after my regular job at the library). I wrote it in the proper tense, but It got edited into semi-unreadability (no past tense allowed).
Years later I was approached by Christopher Stasheff to rewrite Prospero's Isle, and it has been completely done over as straight fantasy (losing the choose your own path aspect... and some of the story lines) and was published as Harold Sheakspeare in The Exotic Enchanter. June 1995, Baen Books; ISBN: 067187666X.
Even tho my story was only one of four in this book, I was honored to see it made the cover. Early on, Vaclav Polacek turns himself into a purple cow. I think you can figure out which are Belphebe and Harold Shea. The artists got Belphebe's dress right in the first cover, and wrong in the second.