This is the best book on the Segal style of self-building popular in the UK. There are three elements to the Segal movement: A practical building method for light wood frame buildings; An ecological approach to building; A track record of owner built communities. This book sticks mostly to the buildings.
Segal built houses are essentially stick buildings made up of ring frames, raised like the bents in a timber frame building. As a structural type they would only be a footnote to post and beam or platform framed building, even if they took off in popularity. They nonetheless provide an attractive, light on the land approach that, aesthetically, is reminiscent of Japanese houses made modern (I suppose one might say Tudor also).
When the book touches on the other themes of ecology and social housing it misses the mark somewhat for most readers, I suspect. These subjects are covered comprehensively elsewhere in the Whole House Book (also Borer and Harris), and the Self Build Book. These themes are also more contingent on local situations and views. For instance the idea that it is more environmentally friendly to burn oak hardwood than say natural gas, because trees when re-grown will be greenhouse gas net-neutral due to the trees' consumption of CO2, is mildly ridiculous. I guess it depends on whose lungs are downwind.