This will make many people very happy.
Anders Kierulf had announced his plans in November already, and now the first stack of ePubs is out …
(I for one still prefer real books, but the ability to play through diagrams in the Go Books app (iOS + macOS) is awesome. Not sure whether that’s possible in the ePubs though.)
One awesome feature of Go Books is that you buy once, use on all your devices (either through the app or as ePub).