Systems

Albert-Laszlo Barabasi , Linked: How Everything Is Connected to Everything Else and What It Means, Plume Books, 2003; ISBN 0452284392.
Many of the networks in programming, social and technical, are "scale-free" as described in this book.

Eliyahu Goldratt and Jeff Cox , The Goal: A Process of Ongoing Improvement, North River Press, 1992; ISBN 0884270610.
The Theory of Constraints is a way of understanding systems and improving their throughput.

Gerald Weinberg , Quality Software Management: Volume 1, Systems Thinking, Dorset House, 1991; ISBN 0932633226.
A system and notation for thinking about systems of interacting elements.

Norbert Weiner , Cybernetics, MIT Press, 1961; ISBN 1114239089.
A deeper, more difficult introduction to systems.

Warren Witherell and Doug Evrard , The Athletic Skier, Johnson Books, 1993; ISBN 1555661173.
A system of interrelated rules for skiing. The big improvements come when adopting the last few rules because being a little off balance is very different than being on balance.