The homepage says:
ATLAS (Automatically Tuned Linear Algebra Software) provides highly optimized Linear Algebra kernels for arbitrary cache-based architectures. ATLAS provides ANSI C and Fortran77 interfaces for the entire BLAS API, and a small portion of the LAPACK API.
On the Ubuntu workstations there is a distro-provided version of the library which will be used by default. That is at version 3.10.1. This version is not particularly optimized. To make the best use of ATLAS it should be compiled on the machine where you want to use it, as the optimization is done at compile time. It is possible to compile ATLAS in your home directory without needing root access. Full details can be found at http://math-atlas.sourceforge.net/atlas_install/.
The documentation that comes with ATLAS is in /usr/share/doc/libatlas-doc. Some of it is text, some of it is Postscript. For LAPACK, consult the LAPACK User's Guide.
