The importance of left ventricular hypertrophy in cardiovascular disease has gained wide recognition. Left ventricular hypertrophy is a highly important risk factor associated with major cardiovascular events, including symptomatic heart failure, particularly in patients with systemic hypertension. Over the past years much has been learned about the genetics, molecular background, prevalence, incidence and prognosis of left ventricular hypertrophy. A variety of noninvasive methods has emerged for detecting left ventricular hypertrophy and the assessment of reversal of hypertrophy. Yet, a lot of controversy remains about the connotations and clinical implications of left ventricular hypertrophy. For instance, in the athlete’s heart left ventricular hypertrophy may constitute a physiological adaptation to pressure overload, which normalizes following discontinuation of strenuous physical activity. On the other hand, in particular in patients with hypertension, left ventricular hypertrophy denotes a serious prognosis in the course of hypertension. In these patients left ventricular hypertrophy should be regarded as a grave prognostic sign rather than an innocent compensatory phenomenon. The distinction between physiologic and pathophysiologic left ventricular hypertrophy has been the basis for this book.