Surface nano- and microtexturing techniques have been used to enhance osseointegration, but how these surfaces work is not well understood. Using the knowledge gained from the cell and molecular biology fields, tissue engineering studies, and their own work, the authors and other researchers have developed surfaces for in vitro and in vivo control of the function of cells and tissues. In the present article, the authors summarize what they know about the process of cell response to surfaces, and what they have done and can do to develop surfaces that control hard- and soft-tissue formation and integration of implants. This article is intended to add to the clinician's understanding of cell and surface interactions, explain why certain surfaces are currently used, and describe what surfaces clinicians may see in the future.