In this text, the self-healing of composite structures with shape memory polymer as either matrix or embedded suture is systematically discussed. Self-healing has been well known in biological systems for many years: a typical example is the self-healing of human skin. Whilst a minor would can be self-closed by blood clotting, a deep and wide cut needs external help by suturing. Inspired by this observation, this book proposes a two-step close-then-heal (CTH) scheme for healing wide-opened cracks in composite structures by constrained shape recovery first, followed by molecular healing.