AppleScript, built into the Macintosh OS, is used by hndreds of companies and countless individuals to automate tasks, control applications, automate Web sites, and more. It's a scripting language that uses natural, English-like syntax — much easier to code than most scripting languages.
Sams Teach Yourself AppleScript in 24 Hours offers a clearly written, well organized introduction to AppleScript. The book starts with running existing scripts, then teaches the reader to write simple scripts to create shortcuts and increase productivity on the Mac OS, then moves on to working with popular Macintosh applications with scripts.