German philosopher of pessimism whose The World as Will and Representation (1819) defined the suffering-and-renunciation tradition.
Closely associated with
Immanuel Kant (the system Schopenhauer built on and revised).
For an intellectual contrast, see
G.W.F. Hegel, German Idealist of the rational unfolding of Spirit — Schopenhauer scheduled his Berlin lectures opposite Hegel's and spent decades attacking Hegel's optimistic system as deliberately mystifying nonsense — the foundational rivalry of 19th-century German philosophy.
The standard scholarly entry points to Arthur Schopenhauer's work:
Bryan Magee (Oxford, populariser-philosopher) — The Philosophy of Schopenhauer (1983);
Christopher Janaway (Southampton, Schopenhauer specialist) — Self and World in Schopenhauer's Philosophy (1989);
David E. Cartwright (Wisconsin–Whitewater) — Schopenhauer: A Biography (2010).
These are the works graduate seminars cite when teaching Arthur Schopenhauer.