The following writings deal with the life and/or philosophy of Schopenhauer: most should be available from larger retailers of new/used books
Title Author/Editor: Publisher & date
Schopenhauer: The Human Character John E. Atwell. Temple University Press (1990)
Schopenhauer on the Character of the World J E. Atwell. University of California Press (1995)
Schopenhauer on Self, World and Morality: Vedantic and Non-Vedantic Perspectives Arati Barua. Springer (2018)
Schopenhauer: A Biography David E. Cartwright. Cambridge University Press (2010)
The A to Z of Schopenhauer's Philosophy David E Cartwright. Scarecrow Press (2010)
Arthur Schopenhauer: Philosopher of pessimism Frederick Charles Copleston. Burns Oates & Washbourne (1947)
Schopenhauer as Transmitter of Buddhist Ideas, (EUP, Series 1, vol. 15) Dorothea Dauer. Herbert Lang (1969)
Little Journeys to the Homes of Great Philosophers. Schopenhauer Hubbard Elbert. Roycrofters (1904)
Arthur Schopenhauer Kuno Fischer. BiblioBazaar (2009)
Schopenhauer: His Philosophical Achievement Ed. Michael Fox. Branch Line (1980)
Schopenhauer Patrick Gardiner. Penguin (1963)
The Riddle of the World: A Reconsideration of
Schopenhauer's Philosophy
Barbara Hannan. OUP (2009)
Schopenhauer (Arguments of the Philosophers) D W Hamlyn. Routledge (2008)
Schopenhauer: Manuscript Remains: vol. l. Early Manuscripts (1804-1818) Arthur Hubscher (Edit), Eric F.J. Payne (Trans.). Berg Publishers (1988)
Schopenhauer: Manuscript Remains: vol. 2. Critical Debates (1809-1818) Arthur Hubscher (Edit.), Eric F.J. Payne (Trans.). Berg Publishers (1988)
Schopenhauer: Manuscript Remains: vol. 3. Berlin Manuscripts (1818-1830) Arthur Hubscher (Edit.), Eric F.J. Payne (Trans.). Berg Publishers (1988)
Schopenhauer: Manuscript Remains: vol. 4. The Manuscript Books of 1830-1852 and Last Manuscripts. Arthur Hubscher (Edit.), Eric F.J. Payne (Trans.). Berg Publishers (1988)
The Philosophy of Schopenhauer Dale Jacquette. Acumen Pub. Ltd (2005)
Schopenhauer, Philosophy and the Arts Ed. Dale Jacquette. Cambridge University Press (2007)
Schopenhauer (Past Masters) Christopher Janaway. Oxford Paperbacks (1994)
The Cambridge Companion to Schopenhauer Christopher Janaway. Cambridge University Press (1999)
Self and World in Schopenhauer's Philosophy Christopher Janaway. OUP (1999)
Schopenhauer: A Very Short Introduction Christopher Janaway. Oxford Paperbacks (2002)
Better Consciousness: Schopenhauer's Philosophy of Value Christopher Janaway & Alex Neill. WileyBlackwell (2009)
Arthur Schopenhauer (Critical Lives) Peter B. Lewis, Reaktion Books (2012)
Schopenhauer Peter B. Lewis. Reaktion (2012)
The Philosophy of Schopenhauer Bryan Magee. Clarendon Press (1997)
Schopenhauer: Pessimist and Pagan V. J. McGill. Haskell House (1971)
The Philosophy of Schopenhauer Bryan Magee. Clarendon Press (1997)
The Living Thoughts of Schopenhauer Thomas Mann, Cassell (1939)
In Search of Schopenhauer's Cat: Arthur Schopenhauer's Quantum-mystical Theory of Justice Raymond B. Marcin. Catholic University of America Press (2006)
Schopenhauer: A Consistent Reading Steven G. Neeley. Edwin Mellen Press (2003)
Schopenhauer and the Wild Years of Philosophy Rudiger Safranski. Harvard University Press (1991)
Schopenhauer: A Guide for the Perplexed R.Raj Singh. Continuum Publishing (2010)
The Great Philosophers:Schopenhauer Michael Tanner. Weidenfeld & Nicolson (1998)
A Companion to Schopenhauer (Blackwell Companions to Philosophy) Bart Vandenabeele. Wiley-Blackwell (2015)
On Schopenhauer’s Fourfold Root of the Principle of Sufficient Reason F. C. White. Brill (1992)
Schopenhauer (Blackwell Great Minds) Robert Wicks. WileyBlackwell (2008)
Schopenhauer's The World as Will and Representation Robert L. Wicks. Continuum (2011)
Schopenhauer Julian Young. Routledge (2005)
Willing and Unwilling: A Study in the Philosophy of Arthur Schopenhauer J. P. Young. Springer (1987)
Arthur Schopenhauer: His Life and Philosophy Helen Zimmern. Dodo Press (2008)