A fairly entertaining entry in the Endless Quest series, one that I read and re-read countless times in my childhood. You are an elf with a magic sword who has to go and rescue his friends from a gang of evil humanoids, including the frost giant and white dragon featured on the cover. The biggest problem with Mountain of Mirrors is that there were too many long blocks of narrative without any decisions to be made; if memory serves, this was much more common among the Endless Quest titles than gamebooks in other series (Choose Your Own Adventure, Fighting Fantasy, etc.)
I should also note that this book is *not* hardcover, nor was it (or the rest of the series) ever published as such. If it had, I'm sure my 10-year old self would have tracked it down...
Mountain of Mirrors (Endless Quest Book #02)
Game World: Dungeons and Dragons
Number of Endings: 14
Plot Summary: You are Landon, an elf sent to discover why vital supply caravans have been disappearing before reaching your isolated village. You end up exploring Shanafria, a frozen mountain with some decidedly unfriendly inhabitants. You must find a way to free a group of elves held captive by ogres and goblins in the Mountain of Mirrors.
This is a Dungeons and Dragons Adventure book.