The book "Factors of Organic Evolution" was written by the outstanding British philosopher Herbert Spencer. The author investigates and analyzes the main factors determining the process of organic evolution. Spencer investigates the nature of the action of natural selection, the adaptation of living organisms to the environment, the role of heredity, and other aspects that affect the evolution of species. The book "Factors of Organic Evolution" is considered a classic work in the field of biology and philosophy of science, which helps to understand important aspects of evolutionary processes in nature.