This pioneering book offers an introduction to photodynamic therapy, a promising new approach in the treatment of complex diseases like cancer and microbial infections in animals. Addressing all aspects, ranging from basics to clinical practice, it presents the history and fundamentals of photodynamic therapy for non-experts. It includes a collection of basic and clinical studies in cancer and infectious diseases, as well as illustrations of successful treatment procedures and future perspectives and innovative applications involving nanotechnology and advanced drug delivery. This valuable resource offers readers insights into how the therapy works and how to apply it effectively in daily practice.