Book excerpt: Biportal endoscopic spine surgery has been rapidly developed recently, and Unilateral biportal endoscopic spine (UBE) surgery may be new stream in spine surgery. UBE surgery is a new concept of surgery that is different from the existing one portal endoscopic surgery, and has the advantage of being familiar with spinal surgeons as the surgical anatomy is similar to a general surgical method, and the learning curve period is short. The 4mm diameter endoscope provides a very clear image, and it can be safely operated under magnified and clear endoscopic view. It is also available to use general surgical instruments in addition to endoscopic surgical instruments during UBE approaches. Currently it is being performed not only in the lumbar spine, but also in the cervical and thoracic spine. In addition, simple laminectomy, disc removal, and spinal fusion are possible. With the advancement of UBE surgery, spinal surgeons from various countries have been performing UBE in recent years, and it is gradually spreading to the world. This will be the first book summarizing from basic to advanced techniques with abundant illustrations and video aid for easy understanding.