The book in your hands develops the best traditions of Russian scientific popular literature. Written in a clear and captivating manner by working theoretical physicists, who are, at the same time, dedicated popularizers of scientific knowledge, it brings to the reader the latest achievements in quantum solid-state physics, but along the way also shows how the laws of physics reveal themselves even in seemingly trivial episodes concerning the natural phenomena around us. Most importantly, it shows that we live in a world where scientists are capable of proving harmony with algebra. - A A Abrikosov, 2003 Nobel Prize Winner in PhysicsThe third edition is considerably extended with three new chapters where the author discusses exciting examples of applications of recent achievements of physics in medicine, nanotechnologies, and physics in cuisine.