This book treats of the irregularities of the heart—bradycardia, block, extrasystole, tachycardia, flutter, auricular fibrillation, pulsus alternans, etc. The investigator or student who desires to specialize in heart disease will not find in it the help that is needed, for the author does not go deeply into fundamentals. Nor will it enable the practitioner to understand or use either the polygraph or the electrocardiograph. But it will aid the practitioner to read and correctly interpret the tracing made by either one of these instruments, and this is its purpose. The chief emphasis is laid on the graphic methods of studying heart disease. Furthermore, while theoretical and pathologic considerations are not ignored, the clinical side is constantly kept in the foreground. The illustrations are good, the explanations clear. The subject of treatment is given a prominent place and is well handled. The bibliography is well selected; there is a helpful index.