Archive.org has been around for years, but there has been a HUGE influx of new art titles in the last few months. To search, make sure you select “texts” in the second box. To download, click “FTP” and save to disc either the pdf or the (generally much smaller) DjVu file. Both consist of page images with linked text files, which means that the text is searchable.
Bridgman, George B., 1939. The Human Machine.
http://www.archive.org/details/humanmachinethea009564mbp
Bridgman, George B., 1920. Constructive anatomy
http://www.archive.org/details/constructiveanat00briduoft
Blake, Vernon, 1927. The Art And Craft Of Drawing
http://www.archive.org/details/artandcraftofdra027904mbp
Crane, Walter, 1914. Line & Form.
http://www.archive.org/details/lineform00cranuoft
De Laszlo, 1934. Painting a Portrait.
http://www.archive.org/details/paintingaportrai000674mbp
Eastlake, Sir Charles Lock. Methods And Materials Of Painting Of The Great Schools And Masters
Volume One
http://www.archive.org/details/handbookofpainti01kugliala
Volume Two.
http://www.archive.org/details/methodsandmateri011267mbp
Guptill, Arthur Leighton,1922. Sketching and Rendering in Pencil.
http://www.archive.org/details/sketchingrenderi00guptuoft
Holmes, C. J. 1920. Notes on the science of picture-making.
http://www.archive.org/details/notesonscienceof00holmuoft
Poore, Henry Rankin, 1903. Pictorial composition and the critical judgment of pictures.
http://www.archive.org/details/pictorialcomposi00pooruoft
Ross, Denman Waldo, 1907. A theory of pure design; harmony, balance, rhythm.
http://www.archive.org/details/theoryofpuredesi00rossuoft
Ruskin, John. The elements of drawing (1920 edition).
http://www.archive.org/details/elementsofdraw00ruskuoft
Richter, Jean Paul, The literary works of Leonardo da Vinci (Volume 1 and 2).
The same illustrated edition of Leonardo notebooks that was reprinted by Dover.
http://www.archive.org/details/literaryworksofl01leonuoft
http://www.archive.org/details/literaryworksofl02leonuoft
Stone, Irving And Jean, 1962. I, Michelangelo, Sculptor (Michelangelo’s Letters).
http://www.archive.org/details/IMichelangeloSculptor
Whistler, James McNeill, 1909. The gentle art of making enemies, as pleasingly exemplified in many instances, wherein the serious ones of this earth, carefully exasperated, have been prettily spurred on to unseemliness and indiscretion, while overcome by an undue sense of right.
http://www.archive.org/details/gentleartofmakin00whisuoft
Ludovici, Anthony Mario, 1912 - The letters of a post-impressionist; being the familiar correspondence of Vincent van Gogh.
http://www.archive.org/details/lettersofpostimp00goghuoft
Gauguin, Paul, 1919. Noa Noa. Translated from the French by O.F. Theis.
http://www.archive.org/details/noanoatranslated00gauguoft
Vasari, Giorgio. Lives of the most eminent painters, sculptors & architects (complete in ten volumes).
http://www.archive.org/details/livesofmostemine01vasauoft
to
http://www.archive.org/details/livesofmostemine10vasauoft
Clark, Kenneth, 1952. Leonardo Da Vinci An Account Of His Development As An Artist.
http://www.archive.org/details/leonardodavincia013645mbp
Hind, Charles Lewis. Drawings of Leonardo da Vinci.
http://www.archive.org/details/drawingsofleonar00leonuoft
Mount, Charles Merrill, 1955. John Singer Sargent - A Biography.
http://www.archive.org/details/johnsingersargen000439mbp
Marillier, H. C. 1912. The Early Work of Aubrey Beardsley.
http://www.archive.org/details/earlyworkwithpre00bearuoft
The later work of Aubrey Beardsley.
http://www.archive.org/details/laterworkofaubre00bearuoft
Quennell, Peter, 1955. Hogarth’s Progress.
http://www.archive.org/details/hogarthsprogress011296mbp
Clapp, 1916 - Jacopo Carucci da Pontormo, his life and work.
http://www.archive.org/details/jacopocaruccidap00clapuoft
Panofsky, Erwin, 1955. The Life and Art of Albrecht Durer.
The classic study of Durer
http://www.archive.org/details/lifeandartofalbr000686mbp
Strange, Edward Fairbrother, 1906. Hokusai, the old man mad with painting.
http://www.archive.org/details/hokusaioldmanmad00strauoft
Whistler (lots)
http://www.archive.org/search.php?query=whistler%20AND%20mediatype%3Atexts%20AND%20collection%3Atoronto%20AND%20subject%3A%22Whistler%2C%20James%20McNeill%2C%201834-1903%22
Clark, Kenneth. The Romantic Rebellion.
http://www.archive.org/details/TheRomanticRebellion
Clark, Kenneth, 1949. Landscape into Art.
http://www.archive.org/details/landscapeintoart000630mbp
Panofsky, Erwin, 1955. Meaning In The Visual Arts - Papers In and On Art History.
http://www.archive.org/details/meaninginthevisu010505mbp
