With the term perioperative anesthesia, it is advocated that anesthesia should be considered an exhaustive process, especially in major surgeries. The purposes of this process are as follows: in the preoperative period, the patient's preparation is provided in different clinical and psychological ways; in the intraoperative period, hemodynamic, surgical, cardiac, and all systems are protected; and in the postoperative period, the patient is recovered from the anesthesia, and short-term complications are prevented. In the postoperative period, in terms of patient safety, anesthesia recovery, and surgical follow-up, it is undoubtedly beneficial to follow up with patients in PACU for the first 24-48 hours before taking them to the service, especially for early complications, prolonged recovery, and close follow-up. PACU, an important constitute of the perioperative process, is also where every risky postoperative patient will be followed. This book aims to examine every stage of the PACU process from a clinical perspective beyond nursing care and support the medical literature. In the book chapters, the expected risks in the patients and those that should be applied clinically in treatment and follow-up processes will be discussed in general.