These two methods form the foundation of where the sampling for most of the other stack methods are applied and the determination of the mass emission rate of their target species. The presentation will cover the origin and evolution of the methods and their derivatives and provide in depth treatments of the theoretical and practical aspects of them.  This will include the method applicability and limitations, equipment, and techniques. Information will also be provided on the current state of the art, evolving technologies, and drivers for improving these measurements.