We consider the problem of representing and extracting morphological information from scalar fields. We focus on the analysis and comparison of algorithms for morphological representation of both 2D and 3D scalar fields. We review algorithms which compute a decomposition of the domain of a scalar field into a Morse and Morse-Smale complex and algorithms which compute a topological representation of the level sets of a scalar field, called a contour tree. Extensions of the morphological representations discussed in the chapter are briefly discussed.