The book is a multi-authored book of 18 chapters comprising the state of the art work of all relevant topics on modern fish histology from 28 authors from ten countries. The topics include Introduction to Histological Techniques, Integument, Fish Skeletal Tissues, Muscular System, Structure and Function of Electric Organs, Digestive System, Glands of the Digestive Tract, Swim Bladder, Kidney, Ovaries and Eggs, Egg Envelopes, Testis Structure, Spermatogenesis, and Spermatozoa in Teleost Fishes, Cardiovascular System and Blood, Immune System of Fish, Gills: Respiration and Ionic-Osmoregulation, Sensory Organs, Morphology and Ecomorphology of the Fish Brain, and Endocrine System. Structural and functional aspects are treated and in a comparative way fish diversity at various taxonomic levels is integrated.