This thesis analyzes three challenges to monetary policy that were relevant for the Swiss case during the 1990s. The first essay focuses on problems of econometric stability in money demand functions in growing economies that experience the typical systematic substitution of outside money through inside money over time. The second essay examines whether the information content of broad monetary aggregates with respect to nominal and real income, and thus inflation is superior to that of narrow monetary aggregates in the presence of financial innovations are present. The third essay examines whether the intriguing behavior of the Swiss franc Deutsche Mark exchange rate during the 1980s and 1990s was consistent with the behavior implied by exchange rate target zone models and to what extent movements in this rate had prompted changes in the monetary policy stance of the Swiss National Bank