Hah, good job, mate. I love it. I've given one credit tp HackerBooks on VibeVoted https://vibevoted.com/hacker-books. It should get a review alongside 11 other projects within the next 24h. I've also added it to SaaSHub. If you give me an email - can add you as the person managing the listing.
I'm wondering - how are you monitoring HN for new books?