This chapter introduces core AI concepts that underlie the discussions in the rest of the book. The concepts discussed here include search, optimization, and the various types of machine learning, namely unsupervised, supervised, semi-supervised, self-supervised, and reinforcement learning. There is also a discussion on feedback offered by humans, which is a core data source for much work in games, emphasizing the ordinal nature of data solicited as human feedback. While this chapter introduces these high-level concepts, it does not discuss actual algorithms. Those are indeed discussed in Chap. 3 .