Jordan Ayan posted a link on Twitter last night to a pdf version of his book "The Practical Guide to Email Marketing". Here's an overview of what the book has to offer:

• 7 Email Strategies
• The Opt-in Process: 10 Steps to Success
• Email Segmentation Strategies
• Guidelines for Effective Email Creative
• Email Metrics: Identifying Insights to Success
• Email Testing: A Checklist for Success
• The Strategic Checklist for Email Success
• The Seven Dirty Words You Can’t Say in Subject Lines

Check it out.