Ah, yes, the author of the Xanth series. [Insert fond memories...] While not "technically" modern litRPG (i.e. there's no stats/leveling), this story does take place in a game world, and it deserves to be recognized as a forefather of LitRPG...
Actually, the book is recognizably LitRPG the way Frankenstein and Kepler's Somnium are science fiction despite existing before the genre was established. This being the case, why isn't Piers Anthony touted as the Father of American LitRPG over that opportunistic fellow who supposes all one needs to do is trademark a genre name?
Yeah, I think Quag Keep is actually the first of our genre. Then Guardians of the Flame. Andre Norton is the Mother of LitRPG (and dragons)?!
I remember reading this book in high school. I loved it! It's one of my favorites from him. Why isn't he named as the father? Because Piers Anthony is a quite person who lives on a tree farm and doesn't need any titles or ego boosting. Titles that are not freely given by others is just to make yourself seem more important than you actually are..