Initially for mechanical engineers, it has been extended and is very widely used by architects and other design professionals. Its file formats (DWG and AutoCAD DXF) have become the default standard for CAD packages.
Version 1 was released in December 1982. The current version is AutoCAD 2002, which was released in June 2001.
External link:
If you're interested in the development of AutoCAD, check out http://www.fourmilab.ch/
John Walker is the founder of Autodesk? and co-author of AutoCAD.