This is the place to come if you want to contribute to the development of the FreeCAD software.
These pages are in the early stage of development. If you can't find the information you are looking for, or have found useful information somewhere we have not linked to, then please leave a comment on the forum and someone will look into it (or, if you are feeling bold, why not edit this page directly!).
The developer documentation comprises the following sections:
This is an ebook under writing on github , please fork and send pull request to contribute.
Latest pdf preview can be downoaded from pdf folder of this git repo 
FreeCAD, though usable in certain areas, is at the beginning of a long way into the CAD mainstream. There is still a lot to do to reach a state where we can compete with commercial software.