"Six Sigma for Everyone" is a good place to start learning about Six Sigma -- what it is, why it matters, and to whom it applies. I have read many books on Six Sigma (and I am a Certified Six Sigma Black Belt by the American Society for Quality) and I found this book to be among the best "summary" guides for the Six Sigma methodology.
George Eckes, the author, addresses both the strategic and tactical components of Six Sigma in this concise book. Eckes also utilizes a "top 10" framework for technical tools, "soft" tools, and common questions for Six Sigma. These top 10 lists help the reader digest common questions (and their answers) in an easy-to-read and understand format.
I recommend this book for anyone interested in learning about Six Sigma as a methodology -- from both a manager's and a practitioner's point of view.
For a much more detailed review of Six Sigma, I recommend The Six Sigma Handbook: The Complete Guide for Greenbelts, Blackbelts, and Managers at All Levels, Revised and Expanded Edition. For those readers interested in more of a "dictionary" type Six Sigma book, I found
The Lean Six Sigma Pocket Toolbook: A Quick Reference Guide to 100 Tools for Improving Quality and Speed to be an excellent reference.
Finally, for a good overview of some of the basic statistics underlying the Six Sigma methodology, I recommend Statistics for Six Sigma Made Easy.
