This book delves into the performance-based design approach, highlighting the necessity for bespoke, adaptive, and cognitive building envelopes that promote sustainable and positive behaviours throughout their lifecycle. A key to unlock the building envelope's potential is the integration of advanced digital tools such as building information modelling (BIM) and digital twin technology, which enable accurate simulation and optimization of energy efficiency, decarbonization, and human-centric design aspects. Moreover, the work emphasizes the importance of a user-centred approach in designing interactive and connected building envelopes, thereby fostering sustainable behaviours among occupants. This focus on user engagement and education in optimizing building envelope utilization not only contributes to reducing the environmental impact but also enhances the quality of life, well-being, and health of occupants. In the era of digital and ecological transition, the book serves as an essential guide to design and operate energy-efficient, responsive, and user-friendly building envelopes, paving the way for a future where the built environment is a significant contributor to sustainability and human health.