The book *Principles of Fluorescence Spectroscopy, Third Edition* by Joseph R. Lakowicz is a comprehensive and accessible reference for students, scientists, engineers, and clinicians working with fluorescence techniques. The author, with extensive experience in the field, presents the principles of fluorescence spectroscopy in a phenomenological manner, combining qualitative explanations with multicolor diagrams, figures, and tables that include experimental data. The book covers a wide range of topics, including the components of spectrofluorometers, fluorescence microscopes, and lifetime instruments, as well as the characterization of fluorophores and environmental influences on their properties. It also delves into advanced topics such as fluorescence lifetime measurements, anisotropy decays, and resonance energy transfer. The book includes useful features such as glossaries, problems and answers, and a CD-ROM with all the figures. However, it does not provide rigorous physical explanations based on quantum theory and quantum chemistry, which are essential for a deeper understanding of the phenomena. The book is divided into two parts: the first part covers classical fluorescence spectroscopy, and the second part focuses on emerging topics with more theoretical explanations. The introduction provides historical context and addresses common difficulties beginners face in the laboratory. Overall, *Principles of Fluorescence Spectroscopy* is highly recommended as a textbook for both teachers and beginning students in the field.The book *Principles of Fluorescence Spectroscopy, Third Edition* by Joseph R. Lakowicz is a comprehensive and accessible reference for students, scientists, engineers, and clinicians working with fluorescence techniques. The author, with extensive experience in the field, presents the principles of fluorescence spectroscopy in a phenomenological manner, combining qualitative explanations with multicolor diagrams, figures, and tables that include experimental data. The book covers a wide range of topics, including the components of spectrofluorometers, fluorescence microscopes, and lifetime instruments, as well as the characterization of fluorophores and environmental influences on their properties. It also delves into advanced topics such as fluorescence lifetime measurements, anisotropy decays, and resonance energy transfer. The book includes useful features such as glossaries, problems and answers, and a CD-ROM with all the figures. However, it does not provide rigorous physical explanations based on quantum theory and quantum chemistry, which are essential for a deeper understanding of the phenomena. The book is divided into two parts: the first part covers classical fluorescence spectroscopy, and the second part focuses on emerging topics with more theoretical explanations. The introduction provides historical context and addresses common difficulties beginners face in the laboratory. Overall, *Principles of Fluorescence Spectroscopy* is highly recommended as a textbook for both teachers and beginning students in the field.