First editions, all first printings. Twelve volumes. Octavo. Each bound in the publisher’s cloth and in the original dustwrappers. 
 
A very good set indeed, in very good dustwrappers, a couple volumes price-clipped or with publisher’s price stickers, some light wear and minor imperfections, volume three a little crinkled to lower panel.
 
A complete set of first editions of the monumental The History Of Middle-earth.
 
After assembling, editing and publishing The Silmarillion, Christopher Tolkien returned to the even greater mass of his father’s unpublished papers giving the full history of Middle-earth.
 
The resulting work - amounting to twelve volumes published over thirteen years - fully encapsulates Tolkien’s vast legendarium: “the body of tales, languages, georgraphy, and other lore from which sprang The Lord Of The Rings and The Silmarillion, and into which The Hobbit ‘intruded’” (Hammond).