This article reviews Monetary Policy Rules, edited by John Taylor. The book evaluates the Taylor rule, a policy rule that specifies changes in the central bank's interest rate according to what is happening to two variables, real output and inflation. Questions are raised about (a) how well the models fit the data; (b) the validity of the assumption that there has been clear improvement in monetary policy; and (c) the rule's microfoundations.

(i) It does not always keep the normative analysis of decision-making distinct from its descriptive analysis, losing sight of the fact that these methods are appealing shortcut approximations, not improvements on, decision-making based on the Savage axioms. (ii) In all the existing applications to monetary policy it analyzes uncertainty about relatively unimportant aspects of models, while making strong, but actually uncertain, assumptions about other, more important aspects.