This presentation provides an overview of definite integrals. It discusses the history of integration developed by Newton and Leibniz. Definite integrals are defined as the limit of Riemann sums over partitions of an interval [a,b] of a continuous function f(x). Some key properties are that definite integrals are independent of variables of integration and reversing limits changes the sign. Definite integrals can be used to calculate areas under curves, between curves, and have many applications such as displacement, change in velocity, work, and finding volumes.