This open access book presents a comprehensive exploration of the challenges and innovations in designing and constructing taller timber buildings (TTBs). It brings together cutting-edge research on key aspects such as structural design, fire safety, and the environmental impact of timber construction. The work emphasizes a holistic approach, addressing not only the technical complexities-like vibration-based assessments, seismic resistance, and long-term behavior-but also integrating themes of circularity, adaptability, and sustainability. The insights shared in this book stem from the collaborative efforts of the COST Action HELEN (CA20139), a network dedicated to advancing knowledge on TTBs. HELEN combines expertise from multiple disciplines and aims to push the boundaries of timber construction, fostering innovative methodologies that improve the durability, resilience, and overall performance of timber buildings. Through these contributions, the book presents practical solutions and visionary frameworks for sustainable, multi-storey timber construction, aiming to shape the future of timber-based architecture in urban environments.