I am always interested in the subject of efficiency in software systems development and read about it at intervals. I recently picked up (Kindle) "Epiphanized: Integrating Theory of Constraints, Lean and Six Sigma" and am working my way through it. In my own experience I've seen Six Sigma (as applied to software development companies) cause a strong focus on "looking backward" resulting in a loss of interest in innovation. Innovation implies uncharted territory (meaning no historical data exists nor are costs/savings/margins easily determined). Six Sigma is very much the opposite in that you are continually looking to refine the execution of prior processes (looking backwards). A bureaucracy also tends to become established where people are placed in designated roles that monitor and advise but do not actually produce anything tangible with the assumption that they are saving money on the project. In a sense they become a tax on the project. As to this book, the first portion is written in a story telling style where the concepts are explained using characters in a story. I do not particularly like this style as it goes to the extreme of having a character with a stuttering problem and episodes of self congratulation by the characters that I find distracting at the least. The constraint concept is an interesting one in that you evaluate the end to end process and not just focus on any particular element. As applied to software I can see some analogy to manufacturing but the phases of design, development, unit testing, QA, deployment and operations monitoring do not easily match up.