MHonArc is a Perl program for converting e-mail messages as specified in RFC 822 and the MIME standard to HTML. MHonArc can perform the following tasks: Convert MH mail folders or UUCP/Unix style mailboxes into an HTML mail archive, Add or remove messages to an existing HTML mail archive generated by MHonArc, Convert a single message to HTML, A main customizable index for mail messages archived, A customizable thread index listing messages by thread, Control over message formatting, and The ability to hook in your own custom message filters.