The efficient utilisation of allocated spectrum for mobile and wireless communication systems has become an important issue due to the increasing number of users and services. Distortion and interference impedes high bit rate transmission and degrades spectrum efficiency by allowing fewer channels in the available bandwidth. Increasing the talk time of mobile equipment requires extending the battery life. The power amplifier is one of the most non- linear and power consuming parts in a transceiver. Extensive research has been carried out on several amplifier linearization schemes to force these devices to deliver maximum efficiency while generating less distortion. The importance of linearity has increased with the introduction of third generation systems and Software Defined Radio concept. These applications require excellent linearity together with broadband operation, which are contradictory properties and achieving one without compromising the other is a challenging task. This book presents harmonic injection and analog polynomial predistortion techniques as potential solutions to these challenges in RF/microwave amplifier design.