ZMailer is a mailer subsystem for the UNIX systems. It is in charge of handling all mail messages that are created on a system, from their creation until final disposition locally or by transfer to another system. As such, the mailer subsystem (the Mail Transport Agent) must interface to local mail reading and composing programs (User Agents), to the various transport methods that can be used to reach other mailers, and to a variety of databases describing the mailer's environment. ZMailer provides this functionality in a package and with a philosophy that has benefited from experiences with earlier mailers. ZMailer provides a capable, robust, efficient subsystem to do the job, which will excel in demanding environments, but is simple enough to fit easily everywhere. WWW: http://www.zmailer.org/