Quarks, Leptons and the Big Bang, Second Edition is a clear, readable, and self-contained introduction to particle physics and related areas of cosmology. It bridges the gap between non-technical popular accounts and textbooks for advanced students. The author concentrates on presenting the subject from the modern perspective of quarks, leptons, and the forces between them. This approach enables readers to grasp the essential concepts more easily than the traditional approach involving the complex interactions of hadrons. It then proceeds to apply these ideas to the modern theory of cosmology. Necessary background material on relativity and quantum mechanics is included but advanced mathematics is avoided.