The last few years have seen the triumph of the theory of cosmological inflation, which explains the origin of the Universe. The theory began in the early 1980s as ideas, models, and scenarios that produced a number of clear, testable predictions. Now, thanks to precision measurements of the cosmic microwave background radiation, digital sky surveys and other observations, these predictions are being confirmed one after another. The book reflects the development of the main ideas of cosmology over the past hundred years, with the main attention paid to the theory of cosmological inflation. The book contains interviews with scientists who made a decisive contribution to the development of this theory. An additional science fiction storyline illustrates the main one using simpler material: the development of the cosmology of intelligent beings in the subglacial ocean of Jupiter's moon Europa. The book is intended for a wide range of readers, although the level of difficulty of the material varies greatly from chapter to chapter. The author proceeded from the principle: “Any reader - from a schoolchild to a professional physicist - will be able to find in the book something that is clear and interesting to him.”