If you are a software engineer you must read "No Silver Bullet" by Fredrick Brooks. If you have "Mythical Man Month" sitting on your shelf and haven't found the time to read it yet. Pick it up and read chapters 16 and 17. It is only about 40 pages and it is worth it. It organizes some thoughts that I had been leaning toward after a discussion with a coworker a year agao. The difference between "accidental" and "essence" problems in software engineering. These two categories are what any change in software development, tool, methodolgy, language, process, anything should be measured against.