The Path of the Puzzles is one of two ways into the inner sanctum of Firetop Mountain.
The two paths seem to have been established with Zagor's authority after the warlock's first resurrection. Overseen by the Inquisitor, the Path of the Puzzles is the alternative to the Path of the Pits. Like the Path of the Pits, it was entered via a tunnel stretching from a large torch-lit cavern filled with crystals.
While the Path of the Pits tested the entrant's combat skills, the Path of the Puzzles tried the power of his mind, presenting him with two mathematical puzzles. 
The Better Option?Edit
The Path of the Puzzles is actually the correct route to take. After successful completion of it, the player can peruse the Inquisitor's library and, provided he has a magnifying glass, can read a chapter of Eye of the Dragon. This chapter will give the knowledge required to summon the Air Elemental of Light, which is needed for combating Zagor's Water Elemental of Chaos.