Moreover;Contingency is a consequence. The outcome of a behavior. What follows behavior. Positive and negative contingencies define the various kinds of reinforcement and punishment. Contingency implies dependency . Events are said to be contingent when the occurrence of one depends on the occurrence of the other. For example, daylight is contingent on sunrise; good grades are contingent on studying or intelligence, or good luck, etc. Contingency is also defined a predictive relationship between two events such that the occurrence of one event predicts the probable occurrence of the other.
List of books: Contingency