General principles of systems design

is an excellent book edited by Jerry Weinberg (isbn 0-932633-07-2). As usual I'm going to quote from a few pages:
It's not the appearance that's the essence of their structure, it's their endurance. Structure is that which stands, which remains, which is unchanged, regardless of its physical properties.
No answer can be both precise and general at the same time.
Aggregation gives protection against the unknown; specialization against the known; and the use of each sacrifices some opportunity to use the other.
The concept of structure... derives from the concept of stability, and not vice versa.
Any representation of a system tends to make certain insights easier at the expense of making others harder.
Failing to yield is the only clue we have to the existence of structure... we can only understand permanence through attempts to change it.
When a system has to deal simultaneously with two threats, protection against one will increase vulnerability to the other.
This conception of the relationship between structure and behaviour is utterly contrary to the most widely held view - namely that structure determines behaviour.
The system responds more slowly in order to respond more surely.
The regulator must be active so that other parts may be passive.
Regulation is invisible - when it works.
Complexity is a relationship between system and observer.
Not only do birds regulate the insect population, but the insects return the favour for the birds.
There is a tendency for complexity in models to rise as the time between sensing and acting grows.

Cognitive surplus

is an excellent book edited by Clay Shirky (isbn 978-1-846-14217-8). As usual I'm going to quote from a few pages:
The real gap is between doing nothing and doing something.
The easier it is for the average person to publish; the more average what gets published becomes.
Language lets us work at the right level of ambiguity.
When opportunity changes a lot, behaviour will as well.
A surprise is the feeling of an old belief breaking.
Many of our behaviours are held in place by inconvenience, and they're quick to disappear when the inconvenience does.
Knowledge is the most combinable thing we humans have.
Behaviour is motivation filtered through opportunity.
The behaviour you're seeing is the behaviour you've designed for.
In participatory systems, "average" is an almost useless concept.
The task isn't just to get something done; it's to create an environment in which people want to do it.