At the scale where matter behaves in extraordinary ways, nanotechnology is redefining the boundaries of science, medicine, and engineering. Principles of Nanotechnology captures this transformation with clarity, precision, and intellectual depth, offering a structured entry into one of the most powerful technological domains of the modern era.This work presents the fundamental principles governing nanoscale systems, bridging core concepts with real-world applications. It explores size-dependent properties, surface phenomena, quantum effects, and material behavior that emerge uniquely at the nanoscale. From nanoparticle design and surface functionalization to drug delivery systems and diagnostic platforms, the book builds a coherent framework that connects theory with practice.Carefully developed explanations guide the reader through synthesis strategies, characterization techniques, and stability considerations, ensuring both conceptual understanding and applied relevance. Emphasis is placed on mechanistic insights, enabling readers to interpret how nanoscale interactions influence performance across diverse applications.Designed for undergraduate and postgraduate students, researchers, and professionals in pharmaceutical sciences, materials science, and nanomedicine, this book serves as both a foundational text and a practical reference.