This is a unique logic puzzle with a number of challenges. For the basic challenge, arrange the 12 books so that there are no consecutive numbers, no books of the same author, & no books of the same height next to each other. Thus, you have 3 variables that you must keep track of to solve the puzzle.

There are 4 different authors on the books (3 books for each author), with the name and title laser engraved into the books. Each author's books are of a different hardwood and easily distinguishable. For example, in the pictures, Shakespeare is of alder, Tolkein is of walnut, King is of oak, and Asimov is of Maple. The books are all made of 1/4" thick wood so they are quite substantial and virtually unbreakable. With the laser engraving feature they will last more than a lifetime.

Once you have solved the basic puzzle, there are more challenges ahead. For greater challenge, fix 2 books from the same author at both ends & the 3rd book at a fixed internal position. In other words, the books o