If you prefer to own the collection, it is widely available from major retailers in several formats: Physical Boxed Sets : Retailers like Penguin Bookshop
The History of Middle-earth is a 12-volume series written by Christopher Tolkien, the son of J.R.R. Tolkien, the famous author of The Hobbit and The Lord of the Rings. The series is a comprehensive guide to the evolution of Middle-earth, a fictional world created by J.R.R. Tolkien. The series includes volumes that cover the development of Middle-earth's languages, geography, and histories, as well as the stories and characters that inhabit this world. the history of middle earth volumes 112 pdf free