Market participants are assumed to behave rationally: free from psychologically determined actions, they follow the economic maximization postulate. Phenomena such as overconfidence, decision-making paralysis, or social influences do not affect the behavior of market participants in the economic sphere. Financial market psychology shows that this is an abstract notion of concerning relevance: in the realistic depiction of financial markets, (consequential) cognitive misjudgments are commonplace. This book discusses psychology in global foreign exchange trading. In the tension between economics and psychology, the foreign exchange market, currency traders, and their typical trading risks are presented. The application of two methods for predicting price developments and attitudes towards market objects is examined. Based on surveys in foreign exchange trading, a comparison between European and American traders is made. The book provides insights into differentiated human behaviors in a trading environment with a daily trading volume of 3 trillion US dollars.