This book analyzes automatic gain control (AGC) loop circuits and demonstrates AGC solutions in the environment of wireless receivers, mainly in wireless receivers with stringent constraints in settling-time and wide dynamic range, such as WLAN and Bluetooth receivers. Since feedforward AGCs present great advantages in this context, as an alternative to conventional feedback AGCs, this book includes a detailed study of feedforward AGCs design -at the level of basic AGC cells, as well as the system level, including their main characteristics and performance.