Hydrocephalus is one of the most common diseases of pediatric and adult neurosurgery. With the introduction of modern neurosurgical procedures, this disease has become a life-long problem.  Even with optimal treatment, there is still significant morbidity and mortality along with a significant cost to the medical system.  This has caused patients and their families to demand improvements in treatments and forced clinicians to evaluate their treatments in large consortiums while utilizing both genetics and technology to improve outcomes or avoid placement of shunt all together.  This text is designed to present the current treatments for hydrocephalus across the lifespan.  The foundation for understanding cerebral spinal fluid (CSF) abnormalities begins with the understanding of physiology and pathogenesis of disease.  These chapters are written by published experts in the field and detail the significant advances in the detection of CSF abnormalities.