The number of proliferation zones in the adult brain is strongly reduced in the transition between fish and tetrapods and even more in mammals compared to non-mammalian vertebrates. While the adult mammalian brain generally contains only two neurogenic areas, the adult teleost brain displays numerous proliferative niches. This book discusses the entire neurogenesis, the sexual reproduction of teleosts and touches base on the occurrence and possible role of heat shock protein 70 in the developing sea bass Dicentrarchus labrax (L.). The cytokine receptor signaling in teleosts are critical mediators of cell-cell communication throughout the life cycle. Over recent years, much has been learned about the cytokine receptor repertoire in teleosts and this book explains how they are utilized. Other topics the authors of this book presented are the central nervous system of the teleosts, their thermoregulatory behavior, the lipid peroxidation in teleosts, and finally, the molecular evolution and environmental acclimation of fish skeletal muscle tropomyosin.