Just received this in my email in case anyone is interested:
For a limited time, the new book “How to Play Go: A Concise Introduction” by Richard Bozulich and James Davies is available as a free in-app ‘purchase’. It’s a straightforward introduction to the game, but still includes example games as well as chapters on opening strategy, elementary tactics, life and death, and handicap go strategy. Get your copy now. And please tell your friends who are curious about Go.
Please note: This FREE “purchase” only works within the iOS app, not on the Web site (because of some peculiarities of the site Anders cannot set the price to zero there). But after “purchasing” it, it will immediately synchronize to all your instances of Go Books (for me: iPad, iPhone, and my Mac).
PeterHB, you’re not the only one who had that problem … I also had to restart the app to force it to load the current catalogue. If that doesn't help, restart your device and then restart the app, that should definitely do it.