"Monism as a connection between religion and science: A man of science" is the work of the famous German biologist and philosopher Ernst Haeckel, which examines the problem of combining religion and science through the prism of monism. The author explores the relationship between the material and the spiritual, trying to find a common language for both fields. He tries to show that religion and science can complement each other and not be antagonistic. The book contains an important contribution to the understanding of the relationship between faith and knowledge, starting an important dialogue between representatives of the religious and scientific worlds."