This book describes the mechanical response of butt, lap and doubler joints. The findings apply to shear connections in civil, aerospace, and other mechanical structures subjected to repeated loading. The findings are intended for engineers and NDE practitioners concerned with the design of new, and inspection and maintenance of existing, shear joints. Estimates of joint fatigue strength are compared with a selection of fatigue strength measurements for aluminum and steel joints. In many cases, the method offers valid estimates and preliminary designs of joints meeting given fatigue strength requirements. The book incorporates the results of over 150 recent and detailed, 2D and 3D finite element analyses of aluminum and steel connections. It includes handbook-type summaries of the results of the finite element calculations, as well as modeling details. The book addresses riveted and bolted joints, aluminum connections for air-frames and automotive bodies, and steel connections for machines and bridges. It is a unique reference for instructors and students in advanced design courses.