New in softcover. Hardcover was published in 2023. This textbook covers the framework of first-principles analysis applied to materials using density functional theory (DFT). It provides a set of hands-on tutorials using the Quantum ESPRESSO package, an open-source software for DFT. The tutorials are well chosen, designed for maximum effectiveness while requiring a minimum of the reader's time, and the book describes how the essential components are combined to create the practical applications based on the idea of modeling practical problems of materials.