Agree with the above. The play's the thing.
I have the book and it's a good way to get you to -think- differently about playing. That's what books are good for. So I'm a better thinker, though not necessarily a better player.
But it is a good book for ideas and besides, you get some of that great Friedland sense of humor.
"Cellar by Flashlight" being one err... stellar example
EDIT: I'll try to be a little les smartassy and do a bit more justice to your question.
The book is fairly advanced so be prepared. It assumes you have some speed and some basic theory and reading skills. That's not a bad thing, since you can grow into it. Come back as you learn and learn more from it.
There is a brief recap of the basics in the begining and some scale exercises. It won't teach you theory, but it's a good refresher if you already have some.
There is a very brief sum of scales and what works with some chords, a section on working with chord progressions, melody and internal melody and one on phrasing.
The CD is full of useless examples (two measure riffs of each type of minor in one key - why bother!) but longer examples of more integrated ideas and the play along cuts are good examples of jazz standards.
No book is a sub for playing and this one will _not_ teach you to improvise. You'll learn as much in a couple hours of jamming, if you can find some one who will put up with your noodleing for a couple hours and is congenial enough to point out your mistakes.
The book gives you ideas to work out when you play. Of those, you'll probably find 2 or 3 you can use. That's about the cost/benefit ratio for most of the MelBay books in this format. Though some things become more clear when you see them in print.
One thing that made the book worh the price for me (and it's not an expensive book, is it?) is the example of how _not_ to do it. Friedland gives an example of a sort-of-OK, ho-hum line and points out what the problems are and gives a better example. I've paid more for some individual lessons and got less out of them.