The textbooks "Theoretical Physics for Future Teachers 1 and 2" aim to provide future physics teachers with the fundamentals of theoretical physics, with a particular emphasis on areas important for high school: quantum mechanics, special relativity, and electrodynamics. The first volume offers a systematic introduction to quantum theory based on the Schrödinger equation and incorporates modern experiments, such as those related to entanglement and the non-locality of quantum mechanics. A simpler, less formal approach to the theoretical concepts and methods has been chosen, allowing students who have not taken mathematics as a second subject the opportunity to understand the theoretical aspects of quantum mechanics. Detailed discussions of new experimental data and pedagogical notes assist in this process.