This part, which consists of two chapters, gives the basic material.

Chapter 1 is a brief discussion of the required background from (modal-free) propositional logic. There should be nothing in this chapter which you don't know already, although perhaps the style of presentation will be new to you. The variety of modal languages are described in Chapter 2. The polymodal versions are introduced right from the beginning and this brings a greater cohesion to the subject.