The book "Dendritic Spines. An Update” aims to describe the ultimate knowledge regarding the dendritic spines-mediated synaptic transmission. The book approaches dendritic spines development and adult spinogenesis, as well as the physiological properties associated to their structural plasticity. The thematic sequence of the chapters that make up the book allows the readers a comprehensive understanding of the neurobiology of dendritic spines and their impact on the integration of the cognitive activity that they mediate, under both normal and pathological conditions.