This monograph provides a unique survey of congenital disorders of the ammonia metabolism. The author deserves special praise for the discussion of prenatal development of fetal ammonia metabolism comprising one third of the book, and also for presenting a wealth of new data. Although it is uncommon nowadays to publish research data in book form, the complete presentation of this information in connection with clinical material is very beneficial. Thus the author provides us with a solid foundation for pathogenetic considerations, diagnostic studies, and therapeutic measures. Discrepancies concerning the ammonia blood levels in normal and pathologic states are clearly spelled out, and the author's own experiments seem to clarify contradictions in older studies. The composition of free amino acids has been analyzed not only in blood, urine, and cerebrospinal fluid of patients but also in normal fetal brain. A series of good graphic presentations and the frequent use of headings