From graphene to topological insulators, Dirac and Weyl semimetals to bosonic systems, Dirac matter unifies the physics of emergent quasiparticles in condensed matter. This book develops a unified framework of Dirac matter based on Dirac equation – originally conceived for electrons – and how it governs the behaviour of excitations in quantum materials and artificial metamaterials. The text explores the universal properties of Dirac matter, from symmetry-protected nodes and topological invariants to interaction effects and impurity resonances. Besides an in-depth introduction into key theoretical concepts and methods, it also provides a review of state-of-the-art research on Dirac matter using real-world examples. A broad perspective coupled with a unified framework allows readers to explore the connections between a variety of ongoing, active research fields. The book is ideal for graduate students and researchers, providing a cohesive and modern guide to one of physics' most dynamic frontiers.