This textbook delivers a comprehensive review of modern spectroscopy encompassing a plethora of various X-ray, photoelectron, optical and laser, as well as radiofrequency and microwave spectroscopic techniques. On the fundamental side, it focuses on physical principles and the impact of spectroscopy on our understanding of the building blocks of matter, while in the area of applications, particular attention is given to those in chemical analysis, photochemistry, surface characterization, environmental and medical diagnostics, remote sensing at short and long ranges, and astrophysics. It features detailed discussion of laser cooling and trapping, Bose–Einstein condensation, ultra-fast spectroscopy, high-power laser–matter interaction, spectroscopy and imaging in astronomy, and various spectroscopic aspects of laser medicine. This thoroughly updated and significantly expanded 5th edition of Svanberg’s Atomic and Molecular Spectroscopy includes a new section on the interplay of optical spectroscopy and multispectral imaging, as well as new coverage of laser-spectroscopic applications to cultural heritage monitoring, ecology, optical mammography, and photoacoustic tomography. For newcomers to the field, it introduces a new section on the fundamentals of quantum mechanics, providing a brief primer to those students without formal experience in the subject. Based on the author’s 50-year career lecturing on spectroscopy and its interdisciplinary applications, the book features over 100 chapter-end questions and close to 3000 references, offering a wealth of meticulously curated experience and pedagogical insight to graduate and advanced undergraduate students throughout physics, chemistry, biology, and materials science.