Analog design has historically been viewed as a voltage dominated form of signal processing. Advances in process technology have brought about new circuit and system techniques which successfully exploit current as the main operating parameter. Ever shrinking feature size of devices on ICs and consequential reduction of power supply voltage can be handled by operating in the current domain. Thus current mode signal processing has resulted in emergence of numerous analog building blocks and operational transresistance amplifier (OTRA) is one among those. Both input and output terminals of the OTRA are characterized by low impedance resulting in circuits that are insensitive to stray capacitances. Using current feedback techniques OTRAs have a bandwidth almost independent of closed-loop voltage gain. This book presents design of OTRA based analog controllers. Extensive literature survey on integrated circuit implementations of OTRA has been included. The simulations have been performed using 0.18 micron MOSIS (AGILENT) CMOS technology parameters. This book will be especially useful to analog designers, researchers, and students pursuing masters program in analog signal processing.