This is more of a personal reflection, or a summary, rather than a review.
Ch1: Introducing Six Sigma and arguing that it's an important methodology for doing business and not "just another initiative-du-jour", also stressing the previous point by emphasising the scientific, technical "data-driven" nature of Six Sigma (it's not just another philosophical perspective) and explaining the statistical meanings of the words "six" and "sigma".
Ch2: Describes the five principles, or pillars, of Six Sigma: the "outputs = processing-of-inputs + error" function ( Y = f(X) + e ), the focus on "causes", the inevitability of "variation", the importance of "measuring", and the concept of "leverage", i.e that there is always a set of few input variables which have the greatest effect on the outputs.
Ch3: Introducing the [R]DMAIC problem-solving approach and describing the "domains of activity", hierarchy of people involved, and the life-cycle of adopting Six Sigma in an organisation. The "domains of activity" explains that Six Sigma relates to the way people "think", the way manufacturing or business "processes" work, the way products and services are "designed" at the beginning, and finally the way top-level managers "manage" a business. The hierarchy explains the various roles of different individuals including but not limited to the management team, support team [IT, finance, HR, ect] and the actual technical problem-solving "practitioners". Finally, the life-cycle section explains the stages an organisation would go through when adopting Six Sigma, from the initial decision and "initialisation" of a system, "deploying" the system by training staff, "implementing" it in a small part of the organisation, gradually "expanding" to different parts of the organisation, and finally the "sustaining" stage where it becomes a second-nature behaviour in the organisation which would, ideally, lead to problems being solved automatically [at low-levels] without having to implement a full DMAIC project.