“Management makes a system work. It helps you do what you know how to do. Leadership builds systems or transforms old ones. It takes you into territory that is new and less well known, or even completely unknown to you.”

Page 116 (italics in source).
The Mythical Man-Month: Essays on Software Engineering (1975, 1995)

23 August 2012 https://twitter.com/gtdguy/status/238837461663490048
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Human Nature and Social Theory (1969)
Context: One will be conducive to cooperation and solidarity another social structure to competition, suspiciousness, avarice; another to child-like receptiveness, another to destructive aggressiveness. All empirical forms or human needs and drives have to be understood as results of the social practice (in the last analysis based on the productive forces, class structure, etc., etc.) but they all have to fulfill the functions which are inherent in man’s nature in general, and that is to permit him to relate himself to others and share a common frame of reference, etc. The existential contradiction within man (to which I would now add also the contradiction between limitations which reality imposes on his life, and the virtually limitless imagination which his brain permits him to follow) is what I believe to be one of the motives of psychological and social dynamics. Man can never stand still. He must find solutions to this contradiction, and ever better solutions to the extent to which reality enables him.
The question then arises whether there is an optimal solution which can be inferred from man’s nature, and which constitutes a potential tendency in man. I believe that such optimal solutions can be inferred from the nature of man, and I have recently found it quite useful to think in terms of what in sociology and economy is now often called »system analysis«. One might start with the idea, in the first place, that human personality — just like society — is a system, that is to say, that each part depends on every other, and no part can be changed unless all or most other parts are also changed. A system is better than chaos. If a society system disintegrates or is destroyed by blows from the outside the society ends in chaos, and a completely new society is built upon its ruins, often using the elements of the destroyed system to build the new. That has happened many times in history. But, what also happens is that the society is not simply destroyed but that the system is changed, and a new system emerges which can be considered to be a transformation of the old one.

Source: Snuff

I laughed. “About as much as any hustler from the Budayeen who can barely read and write his name. I know that the brain is in the head, I’ve heard that it’s a bad idea to let some thug spill it on the sidewalk. Beyond that, I don’t know much.” I did, truthfully, know some more, but I always hold something in reserve. It’s a good policy to be a little quicker, a little stronger, and a little smarter than everybody thinks you are.
Source: When Gravity Fails (1986), Chapter 12 (p. 160).

Source: General systemantics, an essay on how systems work, and especially how they fail..., 1975, p. 90 as cited in: Robert B. Seidensticker (2006) Future Hype: The Myths of Technology Change. p. 45

On his conservation principles.
Interview interview (1995)