This document provides an overview of consideration in contract law. It defines the elements of consideration as requiring a legal benefit and detriment to both parties. The document discusses the concepts of mutuality of obligation, illusory promises, pre-existing duties, modification of contracts, discharge of debts, unliquidated debts, promissory estoppel, and firm offers. It provides examples and hypothetical cases to illustrate these concepts. The learning objectives are to understand the requirements for valid consideration in a contract.