Austin is interested in how and why currencies appreciate and depreciate. The document discusses different exchange rate regimes, including floating exchange rates where a currency's value is determined by foreign exchange markets. It provides examples of factors that can cause a currency to appreciate, such as strong exports or pressure from other countries to increase its value. The document also examines why currencies may depreciate, such as if a central bank encourages a lower value to gain economic advantages, and the impacts of appreciation and depreciation on individuals and businesses.