The hardest single part of building a software system is deciding precisely what to build the most important function that software builders do for their clients is the iterative extraction and refinement of the product requirements. For the truth is, the clients do not know what they want. They usually do not know what questions must be answered, and they have almost never thought of the problem in the detail that must be specified.

We tend to blame the physical media for most of our implementation difficulties; for the media are not "ours" in the way the ideas are, and our pride colors our judgement.

Einstein repeatedly argued that there must be simplified explanations of nature, because God is not capricious or arbitrary. No such faith comforts the software engineer.

Even the best planning is not so omniscient as to get it right the first time.

Well over half of the time you spend working on a project (on the order of 70 percent) is spent thinking, and no tool, no matter how advanced, can think for you. Consequently, even if a tool did everything except the thinking for you - if it wrote 100 percent of the code, wrote 100 percent of the documentation, did 100 percent of the testing, burned the CD-ROMs, put them in boxes, and mailed them to your customers - the best you could hope for would be a 30 percent improvement in productivity. In order to do better than that, you have to change the way you think.

Mediocre design provably wastes the world's resources, corrupts the environment, affects international competitiveness. Design is important.

The boss must first distinguish between action information and status information. He must discipline himself not to act on problems his managers can solve, and never to act on problems when he is explicitly reviewing status.