It gave me a lot of ideas for drills to practice for certain areas of emphasis (edging, spinning).
The Book also breaks down the progression of tricks very well. This will ensure you have the proper foundation to build up to a more advanced trick rather than just throwing it and hoping for the best.
The first disc is super basic but would be a great disc to have a 1st time rider watch. Might help them get out of the water easier.
Look for it on ebay, like Keith said above, you can find it for under $60.
The advanced invert disc is just retarded. It's the way, way advanced trick disc. I started watching it and gave up.