"This brief lays out 10 theories grounded in diverse disciplines and worldviews that have relevance to the world of advocacy and policy change. These theories can help to untangle beliefs and assumptions about the inner workings of the policy making process and identify causal connections supported by research to explain how and why a change may or may not occur. This piece is not meant to be comprehensive of all possible relevant theories and approaches; rather, it introduces and illustrates a handful of theories that may be useful to advocates, funders, and evaluators. While the theories included may have broad applicability, the brief is grounded in the context of US domestic policy. Knowing about existing theories may sharpen your own thinking, provide new ways of looking at the policy world, and give you a leg up on developing your own theory of change. The final section gives concrete examples of the way in which advocates, funders, and evaluators can use this brief in their work." (Introduction, page 1-2)