This thesis consists of three essays in international finance and macroeconomics to study the link between money and economic activity.;The first essay, entitled Liquidity, Exchange Rates, and Business Cycles, presents a two-country, two-good, two-currency model to study the role of liquidity effects in exchange rate determination and the international transmission of economic fluctuations. The monetary authority\u27s injections of cash are funneled into the economy through financial markets. The asymmetry of economic agents\u27 access to the newly injected cash induces liquidity effects. The model provides an exchange rate equation which is different from the simple purchasing-power-parity law of exchange rate determination. Both monetar...