Endless Quest Crimson Crystal adventure D&D hidden picture gamebook 1985

This book is part of a small spinoff from the TSR-published D&D themed Endless Quest gamebook series. The base series has no gameplay mechanics beyond simple choose-your-own-adventure style branching paths. The later Super Endless quest series would introduce Hit Points, limited spell use, items and such. But the Crimson Crystal series has a unique gimmick...

A sheet of transparent red tinted plastic. When held over certain pages, it blocks out the red ink patterns which obscure hidden details - and in the story is represented by a sort of Gem of true seeing your character owns, the Ruby of Seeing.

The first use of it is to verify the identity of a caller at your door - friendly pixie, or disguised hag?

Interior art is decent. Your entire party is shortstacked; being you, Thomas Blackfoot, secretly the infamous ogre-slaying, hag-defying noble thief, Night Shadow, a gnome (?) Named Sir Robert and Michael the Leprechaun.

I've got your Pegasus and I want a thousand gold for it. What a bitch

Probably not the best idea to look at it.

These guys must actually be pretty high level. Jumping worgs like that. Well, it did say you've killed ogres.

So talkative

A scene where the crystal can be used. Most pages are pulp yellow; the crystal compatible pages are heavy and white, with a section of them at the beginning and end of the book only.

Before crystal; with hidden detail faintly visible.

With my replacement not-great transparent plastic, slightly more visible, dweomer around staff revealed.

An interesting scene

My replacement cut from a window cling heart after losing the original. It's too opaque to work properly.

Four books were published; value is moderate and demand relatively low. The series is somewhat obscure and overall not regarded as much more than a gimmick.