I'm not much of a musician (witness my mostly-unsuccessful interludes with guitars and pianos), but I find myself able to produce reasonably pleasant sound via Overtone, and have a great time doing so. (As Sam Aaron has said, it's a great way to translate programming ability into musicality, which seems to have been borne out to some extent.)
My question is, Overtone provides a variety of music theory-related devices (e.g. scales, metronomes, etc) in overtone.music.*, which I've tinkered with but simply don't understand fundamentally. I wonder if anyone could recommend a reasonably approachable music theory book / guide / resource that would mesh well with the facilities that Overtone provides?
Let me answer from the synthesis perspective - which is one of my main interests. Learning to design new synthesisers is a pretty dark art, and most of the books/resources I found take a very theory-centric stance which I found to not be particularly useful.
However, I have found the following practical guides extremely valuable:
Each of these has a slightly different take on walking you through the practicalities of synthesis design inviting you to actually build your own, experiment and play.