A wide range of advanced transmitter architectures which exploit the characteristics of highly efficient power amplifiers for wireless application has been the focus of international research over the past two decades. This full-day workshop combines international academic specialists to outline the most recent activities, achievements and future possibilities in this area. The talks span from circuit design to system level and introduce both progresses in the design of multiband Doherty and highly efficient power amplifiers, as well as their application in digital-centric flexible transmitter architectures. Special emphasis is on transmitters beyond the state-of-the-art technology of envelop tracking. The principles of pulse shaping, outphasing and active load-pulling transmitter architectures will be introduced and their potential will be illustrated through practical implementations and measurement results. An emphasis on critical issues and limitations in realising these amplifiers and systems will be given.