Book excerpt: This volume, Bioresponsive Polymers: Design and Application in Drug Delivery, focuses on recent advancements in bioresponsive polymers and their design, characterization, and applications in varied fields, such as drug delivery and gene delivery. It looks at several carriers for drug delivery and biological molecules using different bioresponsive polymers. To address the many difficulties in existing dosage forms, this book provides information on recent developments to overcome drawbacks of conventional forms of the drug delivery. The chapters cover most areas of bioresponsive polymers, starting with a basic introduction to bioresponsive polymers, followed by chapters on design, characterization, and mechanism of bioresponsive polymers; and applications of drug and gene delivery using bioresponsive polymers via oral, topical, nasal, ocular, and parenteral methods. The book also reviews recent advancements in bioresponsive polymers and advanced applications, such as engineering particulate moieties, biomedical applications, hydrogels as emerging therapy, and electrochemical responses, bioresponsive nanoparticles, and bioresponsive hydrogels.