Hanaan Rosenthal, author of Applescript: A comprehensive Guide to Scripting and Automation on OS X has released a new book, Discovering Automator.
Discovering Automator is also comprehensive, detailing the ins-and-outs of Automator: basic workflow construction, deployment, debugging and advanced topics such as creating shell scripts, Applescripts and plug-ins. The tone is direct and humorous, with screenshots and illustrations making for an easy and informative read.
Discovering Automator is available for $14.99 at Amazon. Your purchase allows you to download over 80 free actions for Microsoft Word, Excel and PowerPoint, being the largest independent collection of Automator actions ever released (many readers of Automator World have asked for MS Office actions, and these alone are worth the purchase price).