2. Market Economics of Uncertainty and Information The principles based on purposeful behavior which have always been at the foundations of economics began to expand to explain the acquisition of information and its use including both the information that might be carried in the actions of others and in the behavior of markets. This evolution was accompanied by the development of more precise principles of behavior as well as modifications of those of classical origin. This chapter reports on the expectations development of individuals and in particular the capacity of individuals to condition their expectations of some events on the observation of multiple other events. That is they measure the implicit conditional subjective probabilities of events that have a stochastic dependence on other observable events.