Behavioural finance & behaviour-oriented financial market theory & is becoming increasingly important as a result of volatility and increasing anomalies on the financial and capital markets. Behavioural finance is concerned with the psychology of investors, and seeks to identify the ways in which investment decisions are reached in the financial and capital markets. What becomes clear in the process & in contrast to the frequent assumption that there is such a thing as a rationally acting homo oeconomicus & is that people act irrationally in this setting and thus often make erroneous decisions. This clear and intentionally concise textbook presents the foundations of behavioural finance against the backdrop of current financial market developments, illustrates the essential components of the theory, and thus provides pointers towards sensible investor behaviour from the viewpoint of behavioural market theory.