From the time immemorial, the heart was considered the seat of soul, repository of feelings and the essence of human existence. Modern (Cartesian) science based on logical analysis and a mechanistic interpretation of physical nature grossly removed these qualities and reduced the heart to a mere pump. Discoverers of the autonomic nervous system adopted a view in which the organ, while it maintained its automatic contractions, was placed under the accelerator-brake control of the autonomic nervous system. The commanding hierarchy encompassed (1) the central autonomic network (CAN), (2) efferent drive via sympathetic and parasympathetic nerves and their ganglionic network. This rather mechanistic view has been challenged by deeper knowledge about the neuroendocrine system, establishing the heart as part of it, and by discoveries of large neural networks, 'little brains' in the gut and - we propose - in the heart. These networks continuously accumulate physical and chemical information of the internal environment, interpret them and produce various messages for the brain and other organs. Apparently, there is dynamic two-way communication going on rather than one with a strictly hierarchical chain of command. This review provides a synopsis of the heart's little brain, the endocrine heart and explores the various avenues of the heart-brain dialogueThe central autonomic network (CAN) is a complex functional entity in the brain that comprises of areas of the medial prefrontal cortex, anterior cingular cortex, prelimbic areas, insular cortex, basal ganglia, periaquaeductal gray matter in the midbrain, and multiple nuclei in the pons and medulla. CAN is the supreme commander of all autonomic functions including cardiovascular control. It engages in a dynamic dialogue with the cortex; thus, CAN is involved in all psychosomatic processes. On the thalamus#hypothalamus-pituitary gland axis, it is part of and presides over the neuroendocrine system. CAN communicates neural messages to and from the heart via vagal (parasympathetic) nerves and sympathetic nerves. Numerous cerebral pathologies can fundamentally affect the cardiac function leading to various arrhythmias, systolic and diastolic dysfunction, stress-cardiomyopathy and even to sudden death. Developing cardiomyocytes in the embryonic heart tube are set to motion by intrinsic cardiac adrenergic (ICA) cells producing catecholamines. The heart' is own conduction system (SA-node, AV-node, bundle of His, Purkinje fibers) quickly develops and it becomes functional even before the development i.e. septation, formation of valves of the embryonic heart would complete. Various origins and types of cells contribute to form the conduction system, e.g. cardiomyocytes, epithelium-derived cells and neural crest cells (NCC). NCCs emanate from the cranial terminal crest area of the embryo and reach the developing heart at the 5th gestational week in humans. As they travel, they differentiate into foremen of septation of outflow tracts, contribute to almost all formation processes in the heart. NCCs are also the progenitors of the cardiac nerves, extracardiac ganglia (plexus cardiacus) and ganglionic network in and around the heart (intrinsic cardiac network). Parasympathetic innervation of the heart precedes sympathetic innervation. The intrinsic cardiac network reaches to the sinus venosus segment and spreads around the atria, pulmonary veins and atrioventricular junction. The anatomical arrangement is implicated as trigger and perpetrator as well as target for therapy in various atrial arrhythmias, including atrial fibrillation. The cardiac plexus and intrinsic cardiac network jointly called as 'heart-brain' consists of cca. 250 thousand neurons. Half of them acts as interneurons modulating information received from others (20%) with mechanical and chemical sensors in the heart, lungs and bronchi. The rest is bidirectional transponders for higher centers. As an internal sensory organ, the heart-