A selection of books from the Internet Archive, a digitisation project of material that is no longer in copyright.

Butt, John, Dickens at Work (1963).
http://www.archive.org/details/dickensatwork007519mbp

Johnson, Edgar, Charles Dickens – His Tragedy and Triumph, Vol. I (1952).
http://www.archive.org/details/charlesdickenshi017722mbp

Johnson, Edgar, Charles Dickens – His Tragedy and Triumph, Vol. II (1952).
http://www.archive.org/details/charlesdickenshi012263mbp

Pugh, Edwin, The Charles Dickens Originals (1912).
http://www.archive.org/details/charlesdickensor00pughuoft

Dexter, Walter, The London Of Dickens (1924).
http://www.archive.org/details/londonofdickens029950mbp

Stephen, Leslie, Life of Dickens
http://www.archive.org/details/lifeofdickens00stepiala

Chesterton, G.K., Charles Dickens A Critical Study (1906).
http://www.archive.org/details/CharlesDickensACriticalStudy

Williams, Mary, The Dickens Concordance: being a compendium of names and characters and principal places mentioned in all the works of Charles Dickens (1907).
http://www.archive.org/details/dickensconcordan00willuoft

Kitton, Frederic George, The Minor Writings of Charles Dickens, a bibliography and sketch (1900).
http://www.archive.org/details/minorwritingsofc00kittuoft

Kent, Charles, Charles Dickens as a Reader (1872).
http://www.archive.org/details/charlesdickens00kentrich

Forster, John, The Life of Charles Dickens (1872).
http://www.archive.org/details/lifeofcharlesdic00forsuoft