ABSTRACT
In this chapter, the authors provide two main reasons to study one-dimensional maps: first, there are many experiments that display first return maps that are almost one dimensional (one dimensional within experimental resolution); second, one-dimensional maps are among the simplest non-trivial dynamical systems. They define unimodal maps as continuous functions having two monotonie branches. These two facts will play a most relevant role in understanding the properties of unimodal functions. An important consequence of the analysis of itineraries is the existence of periodic orbits. The organization of periodic orbits is one of the most interesting subjects concerning the unimodal maps.
