This paper describes the emerging consensus about the 'reaction function' a
pproach to macroeconomic policy. The first section of the paper describes t
he historical emergence of this consensus, as a synthesis of pre-Keynesian,
Keynesian, and monetarist ideas. The theoretical part of the paper present
s the basic framework of the approach and explains a number of extensions,
including: finding the optimal reaction function, avoiding the problem of i
nflation bins, the relevance of the Taylor rule, forward-looking expectatio
ns, extensions to the open economy, and the interconnections between moneta
ry and fiscal policy. The later parts of the paper contain a detailed discu
ssion of some of the practical and institutional issues involved in the imp
lementation of this new framework.