Balzac is a new email application for OS X 10.4 and above, which aims to provide a simple view on your mail whilst allowing fast, sophisticated searches of past correspondence. It has been written to utilise all the advanced services available in OS X, from the address book to the built in spell-checker.
Some of the most interesting features of Balzac include:

• Dynamic views on your mail (ie ‘Smart Folders’)
• User defined categories – messages can be in several categories at once
• An inbox which shows you messages from the last few days
• Fast searches on header fields or text content of all messages
• Customize the way you view your mail with HTML templates for list views and message views
• Send custom HTML email using templates
• Security when viewing HTML email
• Supports Growl notifications