Imagine that you want to learn painting, and they explain to you how to paint the fence beautifully and well, instead of showing paintings by Van Gogh, Picasso or other great artists, and do not even tell you that they exist. Unfortunately, the study of mathematics in schools sometimes resembles the process of observing how paint dries and cracks on a wooden board. In this book, the famous mathematician Eduard Frenkel reveals the hitherto hidden sides of mathematics, allowing us to see in it the beauty and elegance inherent only in the greatest masterpieces. "Mathematics," he says, "is a portal to an unknown world, the key to understanding the deep mysteries of the universe and ourselves." The great mathematician invites us all into this mysterious world.