I have just read "From Billets to Bows" by Glenn St Charles, and am now reading "The Art of Making Selfbows" by Stim Wilcox.
The former turned out to be more of a general historical American archery book - enjoyable and interesting, speaking/typing as an Englishman - but not really what I was expecting.
Stim Wilcox's book is far more of a technical nature, and much more what I was hoping for - very interesting! It can be a little heavy going occasionally, and there is some weak humour which can distract at times, but he does discuss all aspects of the making of self bows from wood cutting to the finished item in great detail. Again, from my view as an Englishman, Wilcox does narrow his range down to mainly discussing Osage flatbows (finding Osage is like finding hen's teeth in the UK!), but his experience and attention to detail shine through, and can be applied to all bows in my opinion. Expensive but worth it.