This review summarizes the present knowledge of suction box dewatering mechanisms. In addition, existing and novel suction box dewatering processes are described for applications in the pulp and paper industry. Three mechanisms that determine the dry content of the web after suction box dewatering are identified, viz. web compression, displacement of water by air, and rewetting. Earlier work focused mainly on the influence of web properties and process parameters for the achievable dry content. That work did not give any information concerning the relative importance of the three mechanisms. There was no measurement of web compression or water displacement. Furthermore, the occurrence of rewetting was neglected by many researchers. A deeper knowledge and, above all, direct measurements are required to better describe suction box dewatering. Some interesting modified suction box dewatering processes were presented in the literature. For example, the use of a membrane on top of the web during dewatering is believed to have the potential for an increase in dry content and energy savings. This increase in dry content is consequently believed to be a result of an increase in web compression.