This article discusses the different types of authority in agency law, including actual, usual, and ostensible authority. It also analyzes a scenario involving the binding authority of an agent in a contract with a third party. The article also covers the doctrine of undue influence and its evolution in courts, including the traditional classification of actual and presumed undue influence, and the refinement of the classification into three classes. The article applies these principles to a scenario involving a transaction between two parties with a power imbalance.