Dendrites are cellular structures essential for the integration of neuronal information. The immense variety but stereotypic architecture of dendritic arbors across the nervous system, have long suggested that dendritic structure and function are organized to meet the processing needs unique to each circuit. Technological advances have greatly pushed the frontiers in research on dendrites at macroscopic and microscopic levels. As such, there has been increasing efforts and knowledge gained in elucidating the structural, functional and molecular mechanisms that regulate the development of dendritic arbors, and that maintain their form and function throughout life. Moreover, as we seek to repair the damaged nervous system, it is clear that a better understanding of how dendrites are perturbed in neurodegenerative disease is needed. In this book, we introduce the basic biology of dendrites, and discuss current knowledge of the mechanisms that control cellular, molecular and functional aspects of dendritic development and maintenance in health and in disease.