Model substrates that present peptide and carbohydrate ligands are becoming important mechanistic tools in cell biology. This review surveys the development of self-assembled monolayers of alkanethiolates on gold as a model substrate for studies of cell adhesion. The review begins with a background that illustrates the opportunity for using tailored substrates in biology and then addresses the characteristics that make monolayers well-suited for these studies. The review concludes with a discussion of recent work that is developing dynamic substrates wherein the activity of immobilized ligands can be modulated in real time.