Probably the best starter text - due to the optimal combination of philosophical depth, mathematical formalism, canonical examples, good writing, and the back section with areas for future research.
Some familiarity with economics (mostly just game theory) is assumed, as is the ability to read some very simple mathematical formulas. One caution as well is that the text is also pitched at a very general level. If you have a specific application area of complex systems you are interested in and cannot read a book that tackles very, very general problems you will be frustrated.
Finally, this is also a book about modeling — not empirical research. And though it is about modeling, it also more about theory than research how-tos (although it does provide helpful ideas in dedicated sections).
Perhaps the strongest suit of the book is that it shows how embedding social systems can change canonical complexity models taken from outside the social sciences. Miller and Page are clear that they are modeling human beings (not ants or bird flocks) even if the foundations are derived from things like forest fires and self-organized criticality in sandpiles.
Complexity is a field full of hucksters and management theory-deep insights. This book accomplishes the rare feat of being both rigorous and accessible. This is the complexity that Malcolm Gladwell won’t tell you about, and that you won’t see on a PowerPoint slide at some business conference.