All the Dukes of Devonshire were men of letters and collectors of books. William, the first Duke, acquired many volumes which had belonged to De Thou, and William, the third Duke, bought largely at the sales of the libraries of Colbert, Baluze, Count von Hoym and other collectors of his time; but William, the sixth Duke, who was born on May the 21st, 1790, may justly be regarded as the founder of the Chatsworth Library in its present form. 'He imbibed a taste for literature and books,' says Sir J.P. Lacaita in his preface to the catalogue of the Library, 'from his mother, Lady Georgiana Spencer, the "beautiful Duchess of Devonshire," and from his uncle George John, second Earl Spencer, who formed what is perhaps the finest private library in existence.' In 1811 he succeeded to the Dukedom, and shortly afterwards endeavoured to add to his library Count M'Carthy's collection, for which he offered twenty thousand pounds, but the offer was declined. He purchased the choicer portion of the books of Thomas Dampier, Bishop of Ely, and he bought largely at the sales of the Edwards, Roxburghe, Towneley and other libraries. In 1815 the Duke removed the books from his other residences to Chatsworth with a view to the formation of a great library there,[95] and in 1821 he purchased John Philip Kemble's splendid collection of plays for two thousand pounds, adding to it four years later the first edition of Hamlet, which he purchased of Messrs. Payne and Foss, the booksellers of Pall Mall, for one hundred pounds. But one other copy of this precious little volume is known to exist, that in the British Museum, which wants the title-page, while that acquired by the Duke is without the last leaf. After the death of the Duke on January the 18th, 1858, the collection at Chatsworth was further enlarged by his successor, who transferred to it some choice books from the library at Chiswick, and also added to it a select portion of the books of his brother, Lord Richard Cavendish, who died in 1873.[96] In 1879 a catalogue of the books at Chatsworth was compiled by Sir J.P. Lacaita, the librarian, in four volumes, and printed at the Chiswick Press. The library is rich in choice and early editions of the Greek and Latin Classics, and the productions of the Aldine Press are particularly numerous and fine. Of the Bibles, the Latin Bible of 1462, and a vellum copy of that printed by Jenson in 1476, are perhaps the most important. As many as twenty-five works from the press of Caxton, and twenty-four from that of Wynkyn de Worde are to be found in the catalogue. Among the Caxtons is a copy of the Recuyell of the Histories of Troye, which once belonged to Elizabeth Grey, wife of Edward IV. This volume was bought at the Roxburghe sale for one thousand and sixty pounds, ten shillings. A magnificent copy of De Bry's Collectiones Peregrinationum, which formerly belonged to FranÇois CÉsar Le Tellier, Marquis de Courtanvaux, is also deserving of special notice. A large proportion of the books are in handsome and historical bindings, and no fewer than twenty-four volumes from the library of Grolier are to be found on the shelves of the collection, which also contains a nearly complete set of County Histories. Among the manuscripts is one of great interest. It is a Missal given by King Henry VII. to his daughter Margaret, Queen Consort of James IV., King of Scotland, and mother of the Lady Margaret Douglas, who later presented the volume to the Archbishop of St. Andrews. The book contains two notes in the handwriting of Henry. On the recto of the fourteenth leaf he has written, 'Remember yo^r kynde and louyng fader an yo^r good prayers, Henry Ky'; and on the reverse of leaf 32, 'Pray for your louyng fader that gave you this booke, and I geve you att all tymes godds bless?g and myne, Henry Ky.' On the reverse of leaf 156 Lady Margaret Douglas has written, 'My good lorde of Saynt Andrews i pray you pray for me that gaufe yow thys buuk—yowrs too my pour, Margaret.'

The Devonshire library also contains a magnificent series of drawings by the old masters, and prints by the early engravers, which were acquired by William, the second Duke. The gem of the collection of drawings is the Liber Veritatis, a set of original designs by Claude Lorrain, which Louis XIV. endeavoured in vain to purchase.