Reference:
http://www.cgal.org/Tutorials/Tutorial_SCG99.ps.gz

The structure of CGAL:

1

Geometric Kernel:

Points, Predicates, and Exactness
Number Types
Cartesian Representation
Homogeneous Representation

Generic Programming and the Basic Library:

Templates in C++
Generic Function with Iterators
Random Points as Input Iterators
Delaunay Triangulation
2
Convex Hull
3
Circulation
Circulation in Triangulations
4

CGAL::Object:

Intersection of two Segments
Voronoi Diagram
5

Traits Classes in the Basic Library:

Triangulation of Terrains: xy-Projection of 3d-Points
6
Independence from the Geometric Kernel
7
Lexicographic Sorting with a Function Object
LEDA Kernel and CGAL Convex Hull

Polyhedral Surfaces:

7
Declaring and File IO
Triangualtion Convex Facets

Curve Reconstruction: crust:

8
Input: a set P of points in the plane
Output: a set S of segments with endpoints in P