One of the most basic and powerful of human cognitive processes is the ability to comprehend and express the fact that two things are similar or different. Often such a similarity or difference is expressed in terms of degree,extent, or quantity. This chapter describes the two most important English constructions used to express similarities or differences of degree or extent-that is, the equative and comparative constructions, respectively. We also briefly discuss the major ways in which the languages of the world express degree-type comparison.