The book conveys the fundamentals and key concepts of theoretical mechanics and special relativity theory as required in teacher training and bachelor's degree programs. It is not a comprehensive presentation in the sense of a master's or previous diploma program, but rather a streamlined exposition of the theoretical foundations of modern physics compared to other textbooks on theoretical physics. The content includes classical mechanics, special relativity theory, solutions and tips for solving problems, a mathematical appendix, as well as units and constants. The target audience includes students in teacher training and bachelor's degree programs in physics, as well as students from related fields and subjects, such as chemistry. The author is Assoc. Prof. Dr. Franz Embacher from the University of Vienna, Faculty of Physics.