The ventricular system comprises a network of interconnected, cerebrospinal fluid (CSF)-filled cavities within the brain that are essential for neurological function. This chapter provides a comprehensive overview of ventricular anatomy, including the lateral ventricles, third ventricle, cerebral aqueduct, fourth ventricle, and central canal of the spinal cord. Each component's anatomical structure, relationships, and clinical significance are examined in detail. The chapter explores the mechanisms of CSF production by the choroid plexus, circulation through the ventricular system, and reabsorption via arachnoid villi. Special emphasis is placed on the pathophysiology, clinical manifestations, and management of hydrocephalus—a condition characterized by abnormal CSF accumulation. Various forms of hydrocephalus are discussed, including communicating and non-communicating types, normal pressure hydrocephalus, and both congenital and acquired variants. Understanding ventricular anatomy and CSF dynamics is fundamental for diagnosing and treating a wide range of neurological disorders, making this knowledge essential for medical students, residents, and practicing clinicians in neurology and neurosurgery.