Tutorial Guide to AutoCAD - 2D Drawing and 3D Modeling Free version
AutoCAD is a complex program ,Here are complete lessons divided into 4 levels of learning.
They are based on AutoCAD 2010, but They are designed to be as compatible with as many versions of AutoCAD as possible. like the new 2015 (differences are noted in the text).
A Tutorial Guide provides a step-by-step introduction to AutoCAD with commands presented in the context of each tutorial.