Abstract: Modeling of data is essential for extracting knowledge and understanding from it. Mostly we think of mathematical modeling as coming from algebraic equations of some kind. What we will discuss in this talk are methods that model data using graphs (in the computer science sense, consisting of nodes and edges) to represent the shape of the data, suitably defined. It becomes a powerful tool for gaining understanding and interrogation of the data. We will describe the methods with numerous real examples from biology and the life sciences.