The book, "Learn ECG in a Day: A Systematic Approach", is a practical guide to medical students and upcoming doctors. It gives clear understanding and interpretation of electrocardiograph (ECG) in a clinical setting in day-to-day practice. The book is simple, easy to understand and one can grasp complete knowledge of ECG in a very short period of time. Interpretation of ECG is an essential part of cardiovascular diagnosis. To read an ECG correctly, one has to be thorough with the basic knowledge of electromechanical system of the heart. It also requires a lot of imaginations and logic conclusions. The book has made an attempt to put forth basic information like the history of ECG, physiology of conduction system of heart, ECG leads, placement of leads in human body, ECG morphology, interpretation of ECG, and the inference drawn from various waves on the ECG strip. The book also includes chapters wholly dedicated to the understanding of arrhythmias and its systematic interpretation.