The normally functioning cell has controls which prevent it proliferating and invading regions of the body from which it is normally excluded. Under certain conditions, the normal rules breakdown and cell proliferation and migration, or metastasis, leads to the formation of tumours. The metastatic behaviour of malignant tumour cells is responsible for the majority of cancer deaths. This book deals with the behaviour and biochemistry of errant cells, a subject that is at the forefront of current reserch in cellular and molecular biology, providing general and specialized information on cell adhesion and mobility in the metastatic process, the behaviour of the cells involved and how they differ from normal cells.