The author analyses mechanisms of the generation of scientific theories and shows that those are changed in the process of historical development of science. He displays three historical types of scientific rationality (classical, non-classical and post-non-classical, which appears in modern science) and shows features of their coexistence and interplay. It is shown that along with the emerging of post-non-classical rationality science increases the sphere of its worldview applications. Science begins to correlate not only with the basic values of technogenic civilization but also with some values and patterns of traditional cultures. The investigation is based on the extensive literature on the history of natural and social sciences. The reader will find in the book authentic historical reconstructions of the processes of the development of classical and quantum electrodynamics, relativity, and conceptions of evolution in biology.