In this talk I will give a definition of relatively hyperbolic groups in terms of relative Dehn functions and then give some relative versions of well-known results for hyperbolic groups. I shall begin by explaining van Kampen diagrams over a group presentation and the concept of the area of a word in the generators. Then I'll define relative presentations and how what a van Kampen diagram over such a relative presentation is. This will allow me to define relative area and eventually relative hyperbolicity. I shall then talk about some properties of relatively hyperbolic groups, including the word problem and quasi-isometry invariance.