Over the past two decades, biodegradable and bioactive biomaterials have moved from niche research interests to foundational components of modern regenerative medicine, drug delivery, and implantable medical devices. Conventional permanent implants have improved quality of life for millions of patients, but they are often associated with long-term complications. In parallel, there is a growing pressure to design materials that are not only clinically effective but also sustainable, resource efficient, and aligned with circular economy principles. Next-generation biodegradable and bioactive biomaterials are distinguished by their ability to couple controlled, predictable degradation with finely tuned biological activity. Despite this rapid progress, current knowledge is fragmented across sub-disciplines, making it difficult for researchers and practitioners to gain an integrated view of design principles, structure-property-function relationships, and translational pathways. Next-Generation Biodegradable and Bioactive Biomaterials provides a state-of-the-art, cross-disciplinary synthesis of concepts, materials, processing strategies, and applications that define the future of transient, regenerative, and functionally active biomaterials. It unifies fragmented knowledge across material classes and application domains, shifts the focus from "biodegradable as an endpoint to "bioactive and programmable" as a design paradigm, and highlights emerging frontiers. Covering topics such as biomedical applications, nanostructure design, and transient biomaterials, this book is an excellent resource for academic researchers, graduate students, clinician-scientists, healthcare professionals, R&D scientists and engineers, and more.