The treatment of patients with cerebrospinal fluid (CSF) pathway disorders (including hydrocephalus, syringomyelia, and arachnoid cysts), requires an understanding of CSF pathways and the cerebral water system. Although outcome with these disorders has improved, only limited treatment options remain available. Ongoing research has continued to improve our understanding of the cerebral water circulation and is starting to provide insight into the pathogenesis and potential treatment options of this common group of disorders. This article reviews current concepts of CSF function and pathways, following the journey of CSF from conception to absorption.