The book numbers 188 pages and has a number of chapters dealing with the group itself, the leadership, the practical elements, bringing in new people, conflict and crisis, and then growth or death of the group. These are further divided into shorter sub-sections that make for easy reading.
Nick offers some useful insights into the minds of those who join and work with magical groups, including whether someone is a leader or a follower, how they will fit in with the egregore, what to do with grades, and what kind of leadership role (guru, round table, panel, three chiefs, etc.) will work best. This latter section is dealt with extremely well, with a number of advantages and disadvantages given for each possibility.
On the practical side of things essential elements like a name, location, and fee structure are addressed, along with ritual work to be carried out at each meeting, and all of the various tools and regalia that may be required, depending on the nature of the group.
The leadership role is given quite a bit of attention given how important it is (and how detrimental a bad leadership can be), but Nick stresses the importance on spreading the work load and strongly encourages the individualising of each member of the group. The section detailing the "warning signs" when someone is about to individualise (which is a good thing, but not without its own painful and sometimes destructive process) is particularly good, especially considering that Nick is advising that potential leaders aid the individualising person as opposed to simply expelling them from the group because of what seems like trouble-making at first.
One problem with the book is the large number of typos, which shows that the editor did not really give it the attention it deserved. Luckily enough these aren't bad enough to distract from the material. Another obvious error occurs with the citing of a book that has not been released yet. In a footnote on page 157 Nick cites Peregrin Wildoak's By Names and Images (information on which can be found here) as being published in 2004. Unfortunately due to delays at Thoth Publications this book still has not been released. Since the copy of Gathering the Magic that I am reading has been updated to a second edition in 2007 I wonder why this footnote wasn't ammended to be more accurate.
Gathering the Magic is mainly focused on ceremonial magic groups, but the advice is generally applicable to all, whether it's a Freemason lodge, a Golden Dawn temple, or a Wiccan coven. Some of the information and advice is fairly common-sense, but it's the kind of common-sense that only occurs when someone highlights it, while many other guidelines Nick gives will not have occured to most group leaders. It is clear that he does not base these things on speculation but on a number of years experience, and thus this book will be of great benefit to those lacking in the experience required to create and grow a successful magical group.