This book provides an introductory yet comprehensive account of James Clerk Maxwell's (1831-79) physics and worldview. The argument is structured by a focus on the fundamental themes which shaped Maxwell's science: analogy and geometry, models and mechanical explanation, statistical representation and the limitations of dynamical reasoning, and the relation between physical theory and its mathematical description. This approach, which considers his physics as a whole, bridges the disjunction between Maxwell's greatest contributions: the concept of the electromagnetic field and the kinetic theory of gases. Maxwell's work and ideas are viewed historically in terms of his indebtedness to scientific and cultural traditions, of Edinburgh experimental physics, and of Cambridge mathematics and philosophy of science, which nurtured his career.