In 1808, Samuel Hahnemann, the founder of homeopathy, began to call the law of similars a "law of nature" - a provocative and controversial statement. 200 years later, homeopathy is still as controversial as it was then. It has, therefore, become necessary to define homeopathy's "state of the art" and especially the state of research on homeopathy.The editors initiated a process based on an interdisciplinary approach. The main objectives were to identify problems in the different fields of homeopathy research and to develop recommendations for further research. The discussion and decision process was based on input from experts with considerable experience in homeopathy representing five different research disciplines: history of homeopathy, case studies, pathogenic trials, clinical research and basic researchThis book summarizes the decision and consensus process by providing (1) an overview of the current state of research on homeopathy and (2) the results.