This book explores circuit designs that accomplish the conversion of an analog signal to a digital signal of a single bit. Starting with the simple comparator, many alternative circuit arrangements and enhancements are elaborated, including hysteresis, negative feedback and a variety of adaptive thresholds. Further, the non-ideal behavior of practical elements and circuits are covered, including input offsets, noise, delay, delay dispersion and oscillation, along with techniques for dealing with these aspects. The wide variety of available components is discussed in terms of performance and applicability. No stone is left unturned in addressing each and every issue that can affect the engineering tasks related to comparators, from the viewpoint of how their performance can affect the system in which they are a critical component.