Both thyroid dysfunction and heart failure show a high prevalence in the adult population. Frequently, in clinical practice, a multidisciplinary approach is useful to optimize the management of patients with these conditions. Although there is no doubt regarding the close link between cardiovascular pathophysiology and thyroid homeostasis, our understanding of this association is far from being exhaustive. Thyroid hormone regulates the expression of cardiac-specific functional contractile and structural proteins and plays a pivotal role in modulating both diastolic and systolic function as well as peripheral vascular resistance. The close relationship between thyroid and heart dysfunction is strongly supported by recent evidence demonstrating that an altered thyroid profile is a negative prognostic predictor in patients with heart failure. The treatment of chronic heart failure, especially in advanced stages of the disease, continues to be an open and challenging field. The potential of novel thyroid hormone therapies that address the molecular biology of thyroid dysfunction and heart failure thus represents an attractive area of multidisciplinary scientific interest. This book is a readable, integrated, and highly up to date presentation of the clinical, pathophysiological, and basic science aspects of thyroid-heart failure interactions. It addresses a complex subject in an approach that targets a large audience of readers.