This book offers a systematic review on 4D printing technologies covering from material to design, manufacturing and their applications, and comprehensively presents the state of the art of 4D printing technologies and their applications to soft robots. This book includes 10 chapters. Chapter 1 covers the history of 4D printing, and the key questions and typical examples about applying 4D printing to the field of soft robots. Chapters 2 and 3 introduce the soft active materials and the related 3D printing technologies that are suitable for 4D printing respectively. Chapters 4&8 discuss the typical examples about manufacturing soft robots by different 4D printing technologies. Chapter 9 introduces the recent progress on 3D printing flexible electronics. Chapter 10 outlooks the challenges and directions about the further application of 4D printing technologies to the field of soft robotics. This book benefits the students and researchers from the fields of mechanical engineering, material science, mechanics, robotics, electrical engineering, bioinspired engineering, and other related fields.