This book emphasizes the importance of the extracellular matrix (ECM) in diseases and explains how this knowledge can be applied to tissue engineering. It provides a comprehensive analysis of the extracellular matrix (ECM) as a key regulator of cellular behavior, tissue architecture, and pathological processes. Integrating current advances in matrix biology, it elucidates how ECM composition, mechanical properties and biochemical signaling shape normal physiology and diverse disease states. The book examines the bidirectional crosstalk between cells and the ECM, detailing how matrix-derived cues influence organelle dynamics, intracellular signaling pathways, and gene regulatory networks. Chapters analyze the contribution of ECM remodeling to cancer initiation, tumor dormancy, metastatic competence, inflammatory responses, and fibrotic progression. Special emphasis is placed on collagen and its post-translational modifications, highlighting how molecular and supramolecular features underpin ECM stability, tissue mechanics, and disease susceptibility. At the same time, the book looks at how important ECM mimicking and ECM-derived materials are for tissue engineering and regenerative medicine. These scaffolds, designed to mimic natural signals in the microenvironment, create platforms for tissue repair, guiding stem cell differentiation and modelling disease mechanisms that are more relevant to the body. By combining molecular knowledge with new biomaterial strategies, the book highlights the potential of ECM-based approaches for new therapies. This work is targeted towards researchers, clinicians and advanced trainees in cell biology, biomedical engineering, oncology and regenerative medicine. It helps to understand how the structure and function of the extracellular matrix (ECM) intersects with disease mechanisms and therapeutic development. By emphasising mechanistic depth and interdisciplinary perspectives, the text provides readers with the conceptual and methodological foundations essential for advancing ECM-focused research and designing the next generation of biomedical interventions.