The book "A critical analysis of the position of Mr. Darwin's work "On the origin of species" in the context of a complete theory of the causes of the phenomena of organic nature. Lecture VI (of VI), "Lectures for workmen, in the Museum of Practical Geology" by the famous scientist Thomas Henry Huxley is an important addition to discussions about the evolution and origin of species. The author carefully analyzes Darwin's theory, highlighting not only its strengths, but also its potential flaws and gaps. In his lecture, he tries to reveal the full picture of the causes of phenomena of organic nature, using scientific evidence and arguments. This book helps readers better understand the complex aspects of evolutionary theory and contributes to the development of scientific thinking."