From what happens inside the atom to how things work on larger scales in the universe, readers can rely on George Gamow's authority and be delighted by his sheer joy of physics. Gamow's breadth of knowledge was astounding - he made major contributions to advances in both cosmology and molecular biology. His elucidation of radioactivity, the Big Bang theory, and even how the genetic code might be transcribed years before DNA was discovered makes him one of the 20th century's greatest scientists. Gamow - the creator of the famous MR. TOMPKINS series - offers here his thoughts how the atom works; the basic laws of chemistry; radioactivity; electromagnetism; the nature of light; and how scientists understand space, time, and motion. These writings were collected from his exhaustive 1958 volume on the physical sciences Matter, Earth, And Sky, now out of print and not available in any other collection.