I am surprised that this was not posted before as it may be up the alley of many on this forum especially as we took on the Banana Riddle earlier this year.
The Secret is a puzzle book that was released in 1982 by Byron Preiss.
There are images and riddles. There are 12 in total. The goal is to match the images to the riddles and find the vase with a key. Only 2 out of the 12 have been found.
One in Chicago, Illinois USA and the other in Cleveland, Ohio USA.
All the clues are to cities within the United States.
Thought I would pass the challenge to all of you riddle solvers. 36 years of treasure searching and only 2 found.
The site below is to another WIKI dedicated to solving the riddles.
X does not always mark the spot.