This dissertation consists of three chapters where we study information transmission in various environments.The first chapter analyzes the effect of the presence of an uninformed sender on the information transmission between an informed sender and the receiver. The sender is uninformed with a positive probability and it is not verifiable whether she is informed or not. In almost all equilibria, the uninformed sender pools with a subset of types of the informed sender. We show that there exists an equilibrium in which the informed sender's cheap talk message conveys more precise information and the informed sender is better off by the presence of the uninformed sender.In the second chapter, a buyer is uncertain of information on product qu...