This book will explore the world of hydrogels, a nature-inspired material that is reshaping technology, medicine, and sustainability. These versatile, water-swollen networks bridge the gap between rigid engineering and living systems, offering biocompatibility, responsiveness, and adaptability. From lignin-based hydrogels for eco-friendly remediation to DNA-programmed architectures for targeted drug delivery, from smart actuators that mimic natural muscles to conductive networks that interface with the brain, this book explores the full spectrum of hydrogel innovation. Written by leading...