The document describes the Tower of Hanoi puzzle. The objective is to move a stack of disks from the starting tower to the goal tower using a third tower, obeying the rules that only one disk can be moved at a time and a larger disk can never be placed on top of a smaller disk. An algorithm for solving the puzzle recursively is presented. The Tower of Hanoi is used in research, computer backups, teaching recursion, and testing frontal lobe functions.