Scripted GUI Testing with Ruby is a practical, quick-moving tutorial based on real life, and real-world GUI applications.

Right out of the gate you’ll start working with code to drive a
desktop GUI. You’ll discover the kinds of gotchas and edge cases that
don’t exist in simple, toy programs. As you add more tests, you’ll learn
how to organize your test code and write lucid examples. The result is a
series of “smoke tests” team will run on Continuous Integration
servers.

Next, we’ll explore a variety of different testing tips and tricks.
You’ll employ a series of increasingly random and punishing test monkeys
to try to crash programs. Table-driven techniques will show you how to
check dozens of different input combinations. See how to use longer
acceptance tests (in the form of stories) to represent the way a typical
customer would use your program.

The book uses examples from Windows, OS X, and cross-platform Java
desktop programs as well as Web applications. You’ll develop test
scripts in Ruby; you don’t need to be a Ruby expert, but basic comfort
with the language will be helpful.

(I would appreciate which people prefer; the publisher's description as above, or the Table of  Contents + What People Are Saying About This Book I used in previous posts.)