Before translating the book, Mu read the encyclopedic three-volume The J.R.R. Tolkien Companion and Guide by Wayne G. Hammond and Christina Scull. The first volume focuses on Tolkien's life and the remaining two on his creation. Carpenter's biography of Tolkien was first published in 1977, but the last volume of the set came out in 2016, which means it includes many new opinions and discoveries, Mu says.
Based on more research and with the help of Dai, who was familiar with the first several volumes of The Complete History of Middle-earth, Mu added the annotations to the original text to provide new and comprehensive information to Chinese readers.
For example, he gives details about the Hobbit party Tolkien organized during a trip to the Netherlands and includes the four reviews by British writer C.S. Lewis on the books of Tolkien. "I'm very proud to say that the annotations in the book are leading in the international Tolkien studies," Mu says.
