This book presents a modern treatment of continuum mechanics suitable for a one-semester course. Constructing a unified theoretical framework for thermomechanical phenomena in a continuum, it emphasizes clarity and accessibility while retaining rigor. The text is systematic, concise and reader friendly, with minimal reliance on advanced or complicated mathematical techniques. The book is organized in a simple and straightforward manner. The six chapters progress from fundamentals to applications. The opening chapters introduce indicial notation, Cartesian tensors, continuum kinematics, and the basic physical laws in both integral and differential forms-laying a foundation valid for solids and fluids alike. Constitutive relations for nonlinear thermoviscoelastic solids and nonlinear Stokesian viscous fluids are then developed and reduced to important special cases. The final chapters focus on elastic solids and fluids, presenting governing equations together with analytical solutions to illustrative problems. Broad in scope yet focused on the essentials, the book covers nonlinear elastic solids and fluids with thermal and dissipative effects within a single framework.