Beyond Tube-and-Wing | free book by NASA

This book details the remarkable efforts to develop a new aircraft configuration known as the Blended Wing-Body (BWB). Responding to a challenge from NASA, McDonnell Douglas Corporation initiated studies in the early 1990s to determine if this new configuration could bring about significant advantages over conventional sweptwing, streamlined tube, and swept-tail designs. After McDonnell Douglas' merger with Boeing, Boeing conducted additional research, development, and design work that led to the fabrication and flight testing of the X-48B and modified X-48C, and, along with NASA, it conducted additional wind tunnel testing under the auspices of NASA's Environmentally Responsible Aviation Program.

https://www.nasa.gov/connect/ebooks/beyond-tube-and-wing.html