Mitogen-activated protein (MAP) kinases (EC 2.7.11.24) are activated within the protein kinase cascades called "MAPK cascade". MAPK pathway contains a chain of proteins in the cell, which sends extracellular stimuli such as mitogens, osmotic stress, heat shock and proinflammatory cytokines, to the DNA in the nucleus. MAPK pathway is the best characterized signal transduction pathway in cell biology, plays a critical role in the infection-induced expression and in cancer. MAP kinase signal transduction system is essential for the rational design of novel pharmacotherapeutic approaches and in pathophysiology studies. The book provides basic idea in modulation of cellular activities such as Apoptosis, Cell Proliferation, Angiogenesis, Cancer, MAPK/ERK Pathway and Anti-Apoptosis. In silico application such as MAPK pathway analysis, molecular studies and docking techniques has been provided in the last chapter.