This book introduces, describes and validates a novel technology for
Conversational Recommender Systems (CRSs). It is targeted for
researchers, teachers and students related to the fields of Machine
Learning and/or E-commerce. Specifically, CRSs are intelligent
E-commerce applications that assist users by supporting an interactive
recommendation process. To this end, CRSs employ some type of a
recommendation strategy, i.e., a specification of the system behavior.
Typically, this strategy is pre-determined in advance and hard-coded
inside the system, thus making it possibly non-adapted to the dynamic
needs of the users. The technology presented in this book allows CRSs to
autonomously learn the optimal (best) strategy for a given
recommendation context, from amongst a set of available ones. The
optimal strategy is best adapted to the users' needs, and is learned
using Reinforcement Learning techniques (a branch of Machine Learning).
We have validated this technology through simulations as well as in an
online evaluation involving several hundreds of real users. Our results
justify the application of this technology in state-of-the-art
E-commerce portals.