Currently, two-thirds of patients undergoing surgery experience acute postoperative pain (POP), which increases the possibility of immediate postoperative complications and facilitates the development of chronic POP. Post-surgical pain does not have a useful biological function, so it must be prevented, avoided, and/or eliminated. The objective of the rational management of acute pain after surgery is to facilitate the rapid recovery of patients with a prompt integration into their usual preoperative activities. The global crisis of opioid abuse has forced us to use other analgesic drugs as well as regional analgesia techniques that are part of effective multimodal analgesia. The non-pharmacological approach has also gained importance in the comprehensive management of acute POP. This book reviews advances in the understanding, management, and complications of POP.