The work systematically presents the theories and experiments that underlie the establishment of modern physics, divided into four major chapters: Einstein's special theory of relativity, the experimental foundations of quantum mechanics, the formalism of quantum mechanics and the foundations of quantum information theory. Being designed for engineering students, most of the fundamental models are supplemented with the presentation of a fundamental application based on the respective theory (the scanning electron microscope, the LASER device or the quantum computer). The work can also be used, if necessary, by other teachers, in the preparation of courses taught to undergraduate or graduate students at engineering faculties.