This highly readable introduction to modern physics was written by a giant of quantum mechanics. Gifted with a rare ability to explain complicated scientific concepts to lay readers, Nobel laureate Max Born presents a step-by-step guide to the understanding of molecules, atoms, subatomic particles, and nuclear physics. Chemical and Engineering News praised Born's narrative as "masterfully discussed . . . easy and delightful," and Philosophy of Science declared that it "should be welcomed by all." Starting with explanations of molecular motion and the kinetic theory of gases, Born advances to the laws of chance, conduction of heat, molecular weight, relativity, mass and energy, electronic charges, gaseous ions, light waves, light quanta, and spectral lines of gases. Subsequent topics include electron waves, Bohr's theory of the hydrogen atom, wave mechanics, Pauli's exclusion principle, cosmic rays, nuclear structure, and dozens of related subjects. Profusely illustrated with helpful figures and drawings, the text includes an extensive appendix that explains the historical and social significance of developments in modern physics.