Okrand's Unabridged Klingon Dictionary was a book about Klingon language. This book was among the works used by the USS Enterprise-A crew in 2293 to present themselves as a Klingon vessel. (Star Trek VI: The Undiscovered Country) The fictional author of this book refers to the real-world inventor of the Klingon language, Marc Okrand. This and other similar items, including A Concise History of the Klingon Empire, were sold together in the 40 Years of Star Trek: The Collection auction. It was lot #777, entitled "UHURA'S KLINGON REFERENCE BOOKS". The winner paid US$2,880 for the lot.