Hello fellow enthusiasts,
I just came across a quora post about what books are out there on recommender systems. It seems we are gettier luckier and the amount of literature is nicely increasing. The answers are from known names who, for example, present at RecSys so I recommend looking into the books they suggest.
https://www.quora.com/Do-you-know-a-great-book-about-building-recommendation-systems
