Cell adhesion is the binding of a cell to another cell or to a surface or matrix. This book discusses the mitochondrial retrograde signalling, a recently discovered cellular signalling pathway, that may work in irradiated mammalian cells. The question whether radiation of visible and near IR radiation can activate this cellular signalling pathway is also reviewed. Novel experimental techniques that probe cellular forces exerted at the sites of adhesive contacts are examined, as well as how these forces can explain the roles of cell adhesion in orchestrating multi-cellular behaviour. Furthermore, the cell adhesion molecule trophinin is discussed, which is uniquely involved in the process of human embryo implantation. The roles of nano and microtopography in the substratum upon cell adhesion are addressed, as well as the effects of substratum and near-substratum mechanical properties on cell adhesion. CADM1, a new mast-cell adhesion molecule that mediates interaction with fibroblasts, nerves, and smooth muscles is discussed in this book, as well as carbon nanoparticles that are used as substrates for cell adhesion and growth. In addition, by reducing cell adhesion and inducing cell proliferation, diabetes increases the risk for oral carcinogenesis. The results of this animal model study are looked as well. Finally, the epithelial cell adhesion molecule, EpCAM, has been studied and subsequently discussed in this book.