Vibration problems, particularly mechanical vibrations, play a significant role in many industries, such as machinery, steel, automotive, and shipbuilding. Naturally, there is a gap between the practical requirements for solving such problems and what is taught in universities and colleges in this field. In the foundational courses of Technical Mechanics for mechanical engineers, vibrations with one and multiple degrees of freedom are primarily addressed. Vibrations of continua often play only a minor role or are offered in special courses for specific areas of specialization. With this book, we aim to reach those students who attend such courses or wish to deepen their knowledge in this area, as well as those engineers in practice who frequently deal with vibration issues.