I just wanted to say that as a newcomer to parametric composition and Opusmodus, Nigel's book has been so helpful. I have it as a pdf in the Utilities section of Opusmodus and work through a chapter a day and copy and paste his code directly into the Composer. 

I know Nigel wrote the tutorials, but his book sets a wider context which I have found very helpful in this beginning stage.

Recommended!

indeed, it is a great introduction to parametric composition. Nigel started working on this book at the time we were working on Opusmodus documentation. It makes me very happy to hear his work is appreciated by so many, He was a great supporter and teacher of algorithmic composition which has spread over many decades. We all miss him dearly.

Note:
There are a few changes to some of the Opusmodus function names since the release of Nigel's book. Some of the examples might end in error.