In this talk, I will start with the definition of a valuation ring and talk about a few of its properties. The aim of the talk is to prove the algebraic geometric result (used in the proof of the valuative criterion) that if we have a point and its generization in a scheme, we can then separate the two by a valuation ring. The talk will be basic and will not require a whole lot of background to understand. Speaker(s): Sridhar Venkatesh (University of Michigan Ann Arbor)