The objective is to make a square and fit them into the large opening of the puzzle. There is only 1 solution and it is very difficult to find. We packaged the puzzle unsolved, but the solution is provided. In the frame I made an extra space to hold one of the pieces so that we could package it unsolved. Our version is made from precision cut woods with at least 4 different woods in each puzzle. Ash, Maple, Walnut, Oak, Mahogany, Birch, Cherry, Alder, and other woods may be used with each puzzle have a little unique look. The pieces are very strong at 1/4" thick and have a nice finish. I also laser engraved the relative size of each piece on the piece itself, which may be helpful to you folks who want to attack this analytically. It also makes identifying the pieces easier if you just want to use the instructions to solve it.
Puzzle measures 9" x 7" in the base. The square opening is about 6.3" x 6.3".

One of the many things I like about this puzzle is that it does not look nearly as difficult as it actually is. People seem to get absorbed in it quite readily as you always seem to get close. In fact though, it is a difficult level 5 (of 5) puzzle.
Originally designed in 1933 by Theodore Edison, son of the famous inventor Thomas Edison, and made by his company Calibron Products of West Orange, N.J. It was offered as just pieces and you were told they made a rectangle and there was only 1 solution. Turns out the only possible solution is a square shape, as verified by Ken Irvine's computer analysis. Ken is working on a full analysis of the puzzle, with excerpts noted below. I will link that analysis here when it is available.