Mutt -- "The Mongrel of Mail User Agents" (part Elm, part Pine, part mh, part slrn, part everything else) is an interactive screen-oriented mailer program that supersedes Elm, Pine, mail and mailx. Features include color support, message threading, MIME support (including RFC1522 support for encoded headers), customizable key bindings, POP3, Delivery Status Notification (DSN) support, and PGP/MIME.