Monetary developments in four of the member countries of the Association of South East Asian Nations (ASEAN)—Indonesia, Malaysia, Singapore, and Thailand—since the early 1980s must be assessed in the context of a remarkably successful economic performance that has contributed to the rapid development of domestic financial markets. The extent of financial liberalization—interest rate deregulation and greater competition in banking markets, as well as the liberalization of restrictions on cross-border capital flows—has been considerably greater than in many other developing countries. It would be surprising if these structural changes in financial markets and the associated rapid growth did not affect the relationship between money, economic activity, and inflation. In many industrial countries that underwent substantial episodes of financial deregulation and financial innovation during the early and mid-1980s, there were significant shifts in the orientation of monetary policies. Several countries found it difficult to retain intermediate targets and moved more toward explicit targets for final objectives, typically inflation.