Since the discovery of the method of homeopathic similarity by Samuel Hahnemann, more than 200 years have passed. But no theory on the use of this method for the treatment of mental illness was never created. Although already at the first experiments in the use of homeopathy, its powerful effect on the human psyche was revealed. The most successful work in this area belongs to the French homeopath Nicolas Marceau, who created a very complete guide to the selection of homeopathic remedies for mental symptoms. This book deals in great detail with the etiology of various mental diseases, the scheme of development and the scheme of choosing the optimal homeopathic treatment.