This impressive work by Sven Brandt deals with the clinical aspects, the pathology, and the heredity of infantile progressive muscular atrophy and its relation to Oppenheim's amyotonia congenita and other morbid conditions with laxity of joints or muscles in infants. The author's study is based on a series of 156 cases, 131 so-called primary and 25 secondary cases, and represents all the material on this disease that Brandt was able to accumulate in Denmark. The author gives an exhaustive survey of publications on "myatonia congenita," infantile progressive spinal muscular atrophy, and congenital or very early cases of muscular dystrophy. He discusses the attempts to differentiate from a pathological and clinical viewpoint between Oppenheim's amyotonia and Werdnig-Hoffmann disease. The clinical syndrome of infantile progressive muscular atrophy, its course and prognosis, the anatomy, etiology, and pathogenesis, the treatment, prophylaxis, and eugenic measures are thoroughly discussed and the pedigrees and case histories reported.