We work in a projective space of dimension n, and consider the equivalence relation of LIAISON among subvarieties of fixed codimension. A beautiful theory has been developed over the last century or so for the case of codimension two. For higher codimension, there are two natural ways to extend the theory: Complete intersection liaison and Gorenstein liaison. The latter has emerged only recently as a viable area of study, and some very surprising connections to the codimension two case have been found. These lead to some tantalizing conjectures. In this expository talk we give an overview of the codimension two case, and we describe the amazing parallels that have been found and have been conjectured for Gorenstein liaison in higher codimension. We contrast this with the situation for complete intersection liaison in higher codimension.