¿Computer-Assisted Surgery (CAS) is a new tool for performing complex procedures in a predictable and safe way. This book is designed to serve as a comprehensive review of Computer-Assisted Surgery, covering the current status of both research and applications. CAS includes Virtual Preoperative Planning (VPP) and Intraoperative Virtual Navigation (IVN), which are a set of technologies used to measure oncological margins in 3-Dimensions (3D), to locate small intraosseous tumors and apply controlled resections preserving anatomical structures. During VPP, patient acquired multimodal images are processed and an interactive virtual scenario is created. This can then be used as a platform to measure oncological distances and preplan osteotomies