Unlock the power of group theory for physicists with this comprehensive guide from The Bookish Owl. Explore the fundamental concepts and essential applications of both discrete and Lie groups, crucial for understanding quantum mechanics, particle physics, and condensed matter. This book simplifies complex topics like permutation groups, point groups, and irreducible representations through clear explanations and numerous solved problems. Delve into matrix exponentials, the circle group, tensor products, angular momentum, and the Lorentz group, gaining insights into the quark model and composite theories. Discover real-world applications in molecular vibration, crystal field splitting, and more. Designed for students and researchers, this resource makes mastering group theory accessible and engaging, enhancing your grasp of physical systems with discrete and continuous symmetries.