Practical Recommender Systems
Not rating this one, because I wasn’t really the right audience for it. I wanted an introduction to recommender system theory, and what I got was … a lot of math. This is a programming manual, with code samples in Python.
There is some theory here, certainly, but there’s no getting away from the fact that recommendation systems are a lot of math, mathematical functions, and graph theory.
This book isn’t for the faint of heart.