I've recently been working on writing adventures for publication. This book is a good value price-wise and the sections are written by people who publish games regularly. It has some good advice and there were some module writing suggestions that someone like myself who has never written modules for a mass audience hadn't considered before. Even if you're just getting it for use in writing modules for your own gaming group, you still might find some kernels of knowledge, especially if you're new to GMing.
[5 of 5 Stars!]