The book "New Approaches to Structural Mechanics, Shells and Biological Structures" is a festschrift published in honor of Professor Chris Calladine, FRS, upon his retirement. After 42 years at the Faculty of Engineering at the University of Cambridge, this work brings together a series of contributions from former students, colleagues, and friends. Professor Calladine has extensively researched structural mechanics, particularly focusing on the plastic deformation of solids and the analysis of thin-walled structures. His works, including significant publications on Engineering Plasticity and the theory of shell structures, have inspired generations of students. Additionally, he has made important contributions to molecular structure research and is known for co-authoring a book on DNA. The papers included in this volume pay tribute to his invaluable support and influence on the research of his students and colleagues.