Every year tens of thousands of people including doctors, medical students, paramedics, nurses, nursing students, and others involved in the care and treatment of cardiac patients, get introduced to echocardiography; aka Echo or Ultrasound of the Heart.The principles of echo are founded in physics although the interpretation of the results, e.g. color flow echo, shows that the use of Doppler shift and the direction of blood flow was not fully appreciated by those developing Cardiac Echo. In physics Doppler shift is the result of an object traveling away from the observer. As a result, the wavelength increases and the color shifts towards red. Objects traveling towards you compress the wavelength and the color shift is towards violet. In the world of Echocardiography, physicians flipped this scenario and red is blood flowing towards the transducer placed on the chest. Thus in physics red is away from the observer, while in Cardiology red is toward the observer. This fundamental error was corrected when Transesophageal Echo (TEE) was developed. For this book we will focus on Transthoracic Echo (TTE) - or conventional echo. Nonetheless, the principles remain the same and this book will provide you with the basic information you need to know, to understand Cardiac Echo.