This is the ACT-R 7 source code distribution. These directories contain all of the Lisp code needed to run ACT-R 7 and also include a tutorial introduction to using ACT-R, a GUI for inspecting and debugging models called the ACT-R Environment, software documentation for ACT-R and the Environment, optional extensions which have been written for ACT-R, and also some example code showing ways of extending the system. Instructions on how to load and run ACT-R and the ACT-R Environment can be found in the QuickStart.txt file in the docs directory. The tutorial units are located in the tutorial directory, and that is the recommended starting point for those new to ACT-R. More detailed information about the software can be found in the reference manual and the Environment manual which are located in the docs directory. There is also a document called "differences-between-6-and-7" in the docs directory which contains slides highlighting the most significant differences between ACT-R 6 and ACT-R 7. For more information or to download the most recent version of the ACT-R software please visit the ACT-R website at: <http://act-r.psy.cmu.edu>.