Abstract
In this chapter, we present some of the known results about the concept of approximate fixed points of a mapping. In particular, we discuss some new results on approximating fixed points of monotone mappings. Then we conclude this chapter with an application of these results to the case of a nonlinear semigroup of mappings. It is worth mentioning that approximate fixed points are useful when a computational approach is involved. In particular, most of the approximate fixed points discussed in this chapter are generated by an algorithm that allows its computational implementation.