An email program included with Apple Inc.'s Mac OS X operating system.

There have been three versions released to date:

Version 1
Included in all versions of Mac OS X up to Mac OS X v10.3, was integrated with other Apple applications such as Address Book, iChat, and iCal.  Some of its features include rules for mailboxes, junk mail filtering and multiple account management.


Version 2
Introduced with Mac OS X v10.4 "Tiger" in April, 2005, messages are stored in a proprietary single message-per-file format (with suffix .emlx) in order to permit indexing by Spotlight.

Some of the new features in Version 2 included:

• "Smart mailboxes" using Spotlight technology to sort mail into folders.
• The ability to flag messages with a low, normal or high priority and to use these priorities in mail rules and smart mailboxes.
• Tools for resizing photos before they are sent (to avoid too-big e-mail attachments).
• The ability to view e-mailed pictures as a full-screen slideshow.
• Parental controls to specify who is allowed to send e-mail to children.
• HTML message composition.

Version 3
Introduced with Mac OS X v10.5 Leopard, it now includes personalized stationery which is handled in standard HTML format.  Mail 3 offers Notes and To-dos which can be synced with iCal and it also introduced a built-in RSS reader. In addition to .Mac subscription service it is now possible to sync address book details with Yahoo! contacts.  Mail 3 also introduced IMAP IDLE support.

A step by step guide to setting up and administering mail will be published shortly.