Policy Analysis by Design examines the approaches to public policy taken by those who try to teach it, write about it, and influence it through major analysis.  Bobrow and Dryzek systematically compare the five major contending analytical frames of reference: welfare economics, public choice, social structure, information processing, and political philosophy.  The workings of each frame are illustrated by means of a common, if imaginary, policy case - air pollution in the hypothetical Smoke Valley.