Hyperammonemia is a metabolic condition characterized by increased concentrations of ammonia in the blood. Due to the neurotoxic effects of ammonia, a nitrogenous compound, it is a highly dangerous condition, particularly during infantile and early childhood development. Ammonia-induced damage to the brain may fast become irreversible depending on the duration and extent of hyperammonemia. Despite this, the mechanisms by which brain function is severely hampered or irreversibly destroyed have not yet been fully elucidated. This book brings together basic scientists and researchers, as well as clinicians caring for pediatric or adult patients, in an effort to shed light on the various biochemical, analytical and clinical aspects of hyperammonemia; it covers current approaches and the latest advances in state-of-the-art management, as well as providing future perspectives on the condition.