This book is a simple, accessible overview of a simple, accessible methodology (Lean Six Sigma).
This book will not make you a specialist, nor a Green Belt (let alone a Black one), but will give you a good introduction to the concepts, methodology and tools of Lean Six Sigma. It also presents the Lean Six Sigma methodology mostly as plain common sense, which can be applied in practical contexts already on the basis of the content of this book.
The book also contains a useful set of web and book references that can be accessed for further reading and information.