Huntington’s disease is one of the most common hereditary neurodegenerative diseases, which remains practically incurable, inevitably leading to the disability of patients and premature death. A fairly wide prevalence in the world, the special severity of the course, the almost complete penetrance of the mutant gene, the peculiarity of clinical and genetic correlations in Huntington’s disease have attracted researchers specializing in neuroscience for many years. The study of the molecular neurobiology of Huntington’s disease over the past decades has largely contributed to significant progress in molecular biology, genetics, and many other biomedical disciplines. At the same time, Huntington’s disease has become a “model” disease in resolving issues of genetic counseling and prognostic testing in modern medical genetics. The review provides brief facts on the history of the study of the disease, including mapping and identification of the mutant gene. The issues of etiology and pathogenesis, molecular genetics of the disease, epidemiology, diagnostics, and differential diagnostics are discussed in detail. The spectrum of clinical manifestations of Huntington’s disease, its various forms, and course features are presented. From a modern perspective, the problem of developing valid biomarkers of both the manifest and the asymptomatic stages of the disease, as well as the course of the pathological process, are highlighted. The main issues of primary and secondary prevention of Huntington’s disease, bioethical principles of conducting genetic counseling for families burdened by this disease are outlined. The approaches to the symptomatic treatment of Huntington’s disease are described, a review of the main promising experimental therapeutic methods that can potentially slow down or stop the progression of the disease, as well as prevent its manifestation in asymptomatic carriers of the mutant gene, are presented. An important contribution of patient organizations to addressing issues affecting the interests of burdened families, scientific and clinical research on the disease was noted. Literature was searched and analyzed using the databases of Scopus, Web of Science, Pubmed (MedLine), eLibrary.