mmmm... perhaps you are refering to "Rayuela", a 1963 book from the also Argentinian writer Julio Cortázar (another great great one, hey, man, what's the heck with you Argentinians! :D ), that gives name to that Spanish videogames Jam I was talking about, having this two great authors as a leitmotiv.
And in the sake of truth, I have read about some medieval non linear books or that required "dice rolls". I will search the info, because I don't remember very well, really ^.^