Liber Veritatis; Or A Collection Of Prints, After The Original Designs Of Claude Lorrain; In The Collection Of His Grace The Duke Of Devonshire. Executed By Richard Earlom, In The Manner And Taste Of The Drawings. To Which Is Added A Descriptive Catalogue Of Each Print; Together With The Names Of Those For Whom, And The Places For Which, The Original Pictures Were First Painted. (Taken from the Hand-writing of Claude Le Lorrain on the Back of each Drawing) And Of The Present Possessors Of Many Of The Original Pictures. Volume The First. (- Third.)

Vol. I: 14 p., frontis. (port.), pl. 1 - 100. - Vol. II: 5, [1] p., frontis. (port.), pl. 101 - 200. Plate no. 132 is misnumbered 182. - Vol. III: [8] p., frontis. (port.), pl. 1 - 100.

The title and imprint vary in the third volume: 'Liber Veritatis; Or A Collection Of Prints, After The Original Designs Of Claude Le Lorrain; In The Collection Of His Grace The Duke Of Devonshire, Earl Spencer, Richard Payne Knight, Benjamin West P.R.A. Charles Lambert, Edward Turnor, George Gosling, And Joseph Farrington, Esqrs. Executed By Richard Earlom, In The manner And Taste Of The Originals. Volume The Third. London: Published By Hurst, Robinson, And Co. Successors To Messrs. Boydell, No. 90, Cheapside. Printed By Thomas Davison, Whitefriars. 1819.'

No publication-date is given on the title-page of Volume I, but its dedication carries the date of 1777 and its frontispiece that of 1777 March 25. Its numbered plates carry the dates of 1774 Jan. 1 (pl. 1-20, 26, 27), 1774 Apr. 25 (21-5, 28-40), 1774 Aug. 1 (51-60), 1774 Sep. 1 (47-50), 1774 Oct. 1 (41-6), 1774 Nov. 1 (61-80), 1775 May 1 (81-100). No publication-date is given on the title-page of Volume II, but its frontispiece carries the date of Feby. 1819, and its numbered plates carry the dates 1775 Sep. 1 (pl. 101-20), 1776 Jan. 1 (121-40), 1776 June 1 (141-6), 1776 Sep 2 (147-60), 1776 Dec. 3 (161-80) and 1777 Mar. 1 (181-200). The publication-date of 1819 is given on the title-page of Volume III, and its frontispiece carries the date of Feb. 1 1819. Its numbered plates carry the dates of 1802 Jan. 20 (pl. 1-20), 1803 Dec. 1 (21-40), 1807 Jun. 1 (41-60), 1810 Dec. 1 (61-78), 1817 May 1 (83-6), 1817 May 2 (79-82, 87-100).

The RIBA catalogue records a different issue of the work, in which Volumes I and II have title-page imprints reading 'Published by the Proprietor, John Boydell, Engraver, in Cheapside, London. MDCCLXXVII' and Volume I has only 12 pages of text, and in which the frontispiece portrait of Earlom in Volume II (carrying the date of 1819) is bound into Volume III as a second frontispiece to that volume. This suggests that in 1819, when Volume III was first published, volumes I and II were reissued with undated cancel title-pages and the Earlom portrait added as a frontispiece to the second volume.

This publication is an expression of the enduring admiration for Claude's landscape paintings and of the eighteenth-century interest in drawings for their own sake. The original sketch-book, which was Claude's own record of his paintings, was called by the artist his 'Libro d'Invenzioni' or 'Libro di Verità'; and it is not clear why Boydell chose to give it a new, Latin name. Earlom's plates evoke the manner of drawings, but, as Kitson points out, they are not always very accurate. Nor were the original drawings always close representations of the paintings - Claude sometimes modifying the overall shape of the composition, and generally paying much more attention to some details than to others, as if they were rather aides-memoires to himself than meticulous safeguards against imitations and forgeries.

The plates of Volumes I and II show the 195 drawings of the Liber and five drawings by Claude added to the Liber by his heirs. The Liber consisted of a series of reduced-size rough copies by Claude of almost all his paintings from about 1635 to his death, many of them carrying dates and names of recipients. They all show landscapes, linked in some cases to Christian subjects, in others to Greek or Roman myths.This chronologic record of Claude's work had been acquired by the second Duke of Devonshire before 1728; and it is now preserved in the British Museum.

The plates of Volume III, despite the wording of the title, show other, miscellaneous drawings by Claude from various British collections (about a quarter of them are now generally regarded as not being by Claude).

The frontispiece of Volume I shows the portrait drawing of Claude that appears in the Liber; that of Volume II, a portrait of Richard Earlom; that of Volume III, a portrait of John Boydell.

The plates of Volumes I and II are sepia mezzotints. In Volume III most plates are sepia mezzotints, some combine mezzotint and aquatint; others are aquatint only; others, soft-ground etchings. Plate 45 combines all these methods.