Co-wrote, that is.
A good friend and colleague has written a couple of books over the last number of years, and I had the enjoyable experience of doing the technical review on them. When his publisher asked if he wanted to write a book on developing apps for Apple Watch, Mo said he would—but he'd rather work with a co-author. When he asked if I would like to take it on, I took almost no time to think about it before I answered with a resounding, "Yes!"
We spent a large chunk of last year on this, with a bit of a hiatus around Apple's Worldwide Developer Conference while we anticipated and then digested the announcement of watchOS 2, and we're really quite pleased with the result. The book covers everything an iOS developer with a little bit of experience needs to get going with the watch and make the most of what it offers.
Perhaps like many programmers, I have a long list of half-finished side projects behind me, but—with the support and encouragement of my family, Mo, the team at Peachpit, and our employer—this is one that has shipped and shipped well. That feels good.
If you think it's something that might interest you, there's a sample chapter on the publisher's website. And if you like what you see then of course I'd be ridiculously grateful if you were to buy a copy ;)