Book excerpt: In Volume I, Analysis of Cells and Tissues, we presented a range of protocols aimed at mapping and analyzing the expression of various molecules of pot- tial interest in metastasis research and for examining their production at the genetic level. In this second volume of metastasis research protocols, we move to the level of living cells and tissues and present methodologies applicable to examining metastatic behavior in vitro and in whole animal models. The methods described in the first section of this volume concentrate on the separation of cell lines with high and low metastatic potential, including the genetic modification of cell lines. The assay systems to test defined aspects of the metastatic cascade are then described in Part II and include cell migration assays, assays for matrix degrading enzymes, basement membrane degrading assays, adhesion assays, and assays of angiogenesis. The role of the specific elements of the metastatic cascade assayed in each of these systems in turn must of course be put into perspective relative to their roles in entire living organisms.