DSPAM is a free software statistical spam filter written by Jonathan A. Zdziarski, author of the book Ending Spam (ISBN 1593270526) and other books. It is intended to be a scalable, content-based spam filter for large multi-user systems. DSPAM is distributed under the terms of the GNU General Public License.The project consists of a library, libdspam, which contains the core filtering and storage routines, and command-line and web-based interfaces.