Are you sitting down?
"The original manuscripts represent the heart of the collection. They include holograph renderings (manuscripts in the hand of the author), various sets of typescripts with corrections by Tolkien, and page proofs or galley sheets, also with corrections in the hand of the author. The manuscripts for The Lord of the Rings, 1938-1955, consist of 7,125 leaves (9,250 pages). Included are an advance proof copy of The Return of the King, printed maps of Middle-earth, dust jackets from the original Houghton Mifflin edition, several drafts of a rejected " Epilogue," and manuscript fragments from The Silmarillion (1977). Drawings and sketches, often in preliminary form in the margin of the text, can be found throughout the handwritten manuscripts. Linguistic and philological notes relating to Tolkien's invented languages also appear in the manuscripts, often on the verso of the main text. The documents reflect an extraordinary creative process; as many as 18 drafts exist for a single chapter. Christopher Tolkien, the author's son and literary heir, has presented the history of the composition of The Lord of the Rings in The History of Middle-earth series (Volumes VI, VII, VIII, and IX, 1988-1992).
The Hobbit manuscripts, 1930-1937, which consist of 1,048 leaves (1,586 pages), include a holograph version, corrected typescripts, three sets of page proofs with the author's corrections, a water-color rendering by Tolkien of the dust jacket used by Allen and Unwin, printed maps with corrections, a watercolor of trolls and Gollum by German artist Horus Engels, and the original copy of " Thror's Map." Most of the early holograph is a continuous text with no chapter divisions. The manuscripts for Farmer Giles of Ham, ca. 1930-1938, 1948-1949, comprising 173 leaves (201 pages), include a holograph, typescripts with corrections, and galley sheets with corrections. Mr. Bliss, ca. 1928-1932, includes 39 leaves (61 pages). In addition to the finished booklet which is 50 pages in length, separate " preliminary" drawings and jottings exist. The manuscript is in Tolkien's calligraphic hand, illustrated throughout with ink and colored pencil drawings. Galley sheets and an advance proof copy of the 1982 facsimile edition complete the primary holdings."
And there's more...
"The collection includes books by and about Tolkien, periodicals produced by Tolkien enthusiasts, audio and video recordings, and a host of published and unpublished materials relating to Tolkien's life and fantasy writings."
I was so speechless I had to use quotes directly from Marquette's webpage. It's unbelievable isn't it?