This lecture covers the process of bending in which a sheet is deformed by bending it around a rectilinear axis, resulting in compression and traction stresses on different parts of the sheet. It explains corner folding, V-bending, wedge-folding, and the concept of the neutral surface. The lecture also discusses the geometric relations, bending force, work, and stress distribution during bending. Additionally, it explores the elastic rebound and shrinkage of fibers after relaxation in the case of V-folding, emphasizing the behavior of the material under ideal plastic conditions.