The theory of iteration of rational and entire functions has its origin in fundamental mémoires by Fatou and Julia dating back to 1918–20 and was revitalised in the 1980’s. In this chapter we will give an introduction to the subfield ‘Iteration of polynomials’. The approach to this fascinating part of Complex Analysis is much easier for polynomials than for rational functions and can be accomplished, with a single exception, with the resources and tools developed so far in this text.