A valuable resource and very well done. Rooksby's approach is somewhat off-beat and unconventional, though well grounded. The CD provided is very well considered and produced, neutral and yet not bland or uninspiring, and is well set-up to initiate practice.
I found this book tremendously useful, and in ways beyond it's original intent. Yes it is good for learning practical elements of song-writing. It's also a very good and practical guide to specific aspects in music theory, particularly for pop-music and it insightfully covers stuff i've not seen elsewhere. And in addition, and quite to my pleasure, this is a very useful framework for study to develop a player’s improvisational skills again in ways i've not seen elsewhere.
The book is laid out in eight sections with ninety complete 'lessons' total! Each 'lesson' stands as a separate packet of knowledge, and they build and are organized well. Each has three parts, a chart, a keyboard diagram for each chord voicing in the chart (the book is unique again in that nothing is written in standard (staff) notation), and a chatty description of the meaning and emotional content and feelings of each example and how each would be used. Often there are historical references to where you would have heard this before.
Rooksby is quite clever in the ways he describes things, as for instance his own descriptive term -- 'slush' and 'slush-maker', so that's another fun aspect to this book.
In general the voicings are 'white-note' voicings, so usually things are in C major, or A minor, etc -- so it's up to you to transpose and practice in other keys. This seems a very practical approach and expectation. I also found the absence of standard notation quite sensible and very workable.
There are a few (to many) mistakes in the text, and it doesn't always follow it's own ad hoc descriptive conventions. For instance there is some confusions with notation of inversions and slash chords -- everyone seems to notate this stuff differently, but they'd generally stick to one convention throughout. Also what is not covered and feels missing are rhythmical elements of composition as well as more coverage of melody, though this book is so full of other things there's not room.
I've looked at some of Rooksby's other books, and they also well considered, unique and valuable. I am thinking in particular of his book Lyrics: Writing Better Words which is also excellent.
I'm not certain that Rooksby's guide made me a better songwriter, but it certainly made me a better and more varied pianist, opening my mind to new chord structures that enabled to me to play more expressively. His tips are great, and perhaps others will have more success, or at least different kinds of success, than I did.