This chapter has well written text and 21 well illustrated diagrams and pictures showing pathophysiology and radiographic findings in hydrocephalus. Anatomy and physiology of development of hydrocephalus are described in detail. Incidence, pathogenesis of hydrocephalus along with clinical presentation are given in detail. Investigations in a case of hydrocephalus are described with the help of diagrams and radiographic pictures. Management, prognosis and post operative complications of hydrocephalus are described at the end of the chapter. List of treatment of hydrocephalus in past is summarised in a table. Imaging characteristics in infectious diseases causing hydroceplaus are given in a table.70 references are given for further reading to conclude this chapter.