Economics is a science, but it is a social science; the human factor—particularly beliefs that shape how humans interpret and act on information—plays a substantial role in the behavior of financial markets. Four attributes of beliefs are important to keep in mind: (1) Most concepts and frameworks are shared. (2) Beliefs differ greatly in sophistication. (3) Beliefs are often false. (4) Beliefs do not change easily. From a practical point of view, by emphasizing the importance of individuals’ decisions, the behavioral approach reaffirms that good business judgment is critical in money management.This presentation comes from the Improving the Investment Decision-Making Process: Behavioral Finance and Decision Theory conference held in Marina del Rey, on April 4, 1995.