I have varied interests. But of all the books I've written, the most enjoyable ones have been those on building acoustic guitars from kits.
Building a kit guitar is like using a modern writing program like Word™ to put together a nice looking document, versus the old, defunct way of having hot type created galleys printed, cutting and pasting a layout, etc. It's easier, but that doesn't make it any less capable of high quality.
With a kit, many years of experience and many hundreds or thousands of dollars of machinery are eliminated. What you get in a box is all the separate parts a professional luthier creates himself, ready to work and fit and make into a really nice guitar.
So, these are the books I've enjoyed doing more than others.
As a writer, the most enjoyable projects have been my books on building kit acoustic guitars. I wish I could communicate how fulfilling it is to create a quality guitar without having to have a complete wood shop, lots of machinery, and years of experience.
Modern kits offer the finest woods combined with traditional acoustic designs and they can, with care, create an instrument that any player can be proud of.
I've built twenty-one of them, and have two still in process. It's a wonderful hobby!