CGAL is the Computational Geometry Algorithms Library that is developed by the Esprit project CGAL. The library is written in C++ and makes heavily use of templates, which are a means to obtain generic code.
\stl is the Standard Template Library. Its main components are containers, algorithms, iterators and function objects. This library is part of the forthcoming C++ standard, free implementations are available[^1], and there are some compilers that are already shipped with an implementation of \stl.
\stl is more than a library, it is a framework and a programming paradigm which was adopted by the CGAL project for its library of geometric algorithms.
This document describes in a simplified way the basic features of \stl. After reading this document you should be able to use these features which are used throughout the CGAL library.
This document is neither a reference manual[^2] nor a tutorial for \stl. For the sake of simplicity we sometimes sacrifice exactness. If you compare what is written in this document with what is written in the reference manual you will see that in reality things are slightly more general and hence slightly more complicated.
If you want to develop your own iterators or containers, this is definitely the wrong document for you. We recommend to have a look at the header files themselves as the code is extremely instructive.