This book introduces readers to nine techniques for natural orifice specimen extraction surgery (NOSES) in gastric cancer and fifteen different techniques for NOSES in colorectal cancer, respectively, based on extensive high-quality surgical images. The first part mainly describes the development process of NOSES and preoperative preparation,offering readers a general understanding of NOSES. In turn, the second and third parts elaborate on the surgical procedures for gastrointestinal cancer. All key technical points and operational skills regarding NOSES are covered, and the indications and contraindications are clearly defined. In addition, the book provides a detailed and comprehensive analysis of the hot spots, technical difficulties and key issues with regard to laparoscopic surgery for gastrointestinal cancer. Accordingly, it offers an essential guide for gastrointestinal cancer surgeons and general surgeons.