The main objective of this book is to explore the calculation and structural design of the shear centre in aircraft wing cross-sections. Achieving this aim involves incorporating discussions on torsion and transverse shear specifically tailored for multi-cellular thin-walled and idealised cross-sections. This book is designed for a wide audience, encompassing undergraduate and postgraduate students in mechanical and aerospace engineering, as well as industry professionals engaged in lightweight or skinned structural design and production. It offers numerous practical solved examples and aims to serve as a thorough resource for analyzing torsion and transverse shear in idealized thin-walled structures, with a specific focus on the shear centre analysis of aircraft wing cross-sections. Matlab scripts are included towards the end of the book to facilitate automatic calculation of the shear flow distribution and shear centre location.