GEF (Graphical Editing Framework) is a Java technology, it is a part of the Eclipse framework developed by IBM. It gives developers a full solution for graphical modeling of a java object model, and it can be used in conjunction with other technologies such as EMF (Eclipse Modeling Framework) or GMF (Graphical Modeling Framework), to be able to gain abstraction levels in application development. We created this tutorial because we encountered a lot of problems during the development of a GEF application, and moreover, the main documentation we found about GEF on the Internet and in books (like the IBM Redbook) was more about GEF theoretical concepts rather than practical application about how to use GEF classes. That is the main motivation we had in writing this tutorial, that means to be very pragmatic and useful for the programmer, hopefully.