Biopotential Readout Circuits for Portable Acquisition Systems describes one of the main building blocks of such miniaturized biomedical signal acquisition systems. The focus of this book is on the implementation of low-power and high-performance integrated circuit building blocks that can be used to extract biopotential signals from conventional biopotential electrodes. New instrumentation amplifier architectures are introduced and their design is described in detail. These amplifiers are used to implement complete acquisition demonstrator systems that are a stepping stone towards practical miniaturized and low-power systems.