1. ​Being and Time by Martin Heidegger
2. Hegel's Phenomenology of Spirit by Georg Wilhelm Friedrich Hegel
3. The Republic by Plato
4. The World as Will and Representation, Volume 1 by Arthur Schopenhauer
5. Critique of Pure Reason by Immanuel Kant
6. Simulacra and Simulation by Jean Baudrillard
7. The Prince by Niccolò Machiavelli
8. Pensées by Blaise Pascal
9. Philosophical Investigations by Ludwig Wittgenstein
10. Nicomachean Ethics by Aristotle
11. An Enquiry Concerning Human Understanding by David Hume
12. Beyond Good and Evil by Friedrich Nietzsche
13. The Complete Essays by Michel de Montaigne
14. Ethics by Baruch Spinoza
15. An Essay Concerning Human Understanding by John Locke
16. The Human Condition by Hannah Arendt
17. Creative Evolution by Henri Bergson
18. On Duties by Marcus Tullius Cicero
19. Language, Truth, and Logic by A.J. Ayer
20. Fragments by Heraclitus
21. On Bullshit by Harry G. Frankfurt
22. The Structure of Scientific Revolutions by Thomas S. Kuhn
23. The Conquest of Happiness by Bertrand Russell
24. The Second Sex by Simone de Beauvoir
25. The Analects of Confucius: A Philosophical Translation by Confucius
26. Meditations on First Philosophy by René Descartes
27. The Order of Things: An Archaeology of the Human Sciences by Michel Foucault
28. Theodicy by Gottfried Wilhelm Leibniz
29. Thinking, Fast and Slow by Daniel Kahneman
30. Fear and Trembling by Søren Kierkegaard
31. The Sovereignty of Good by Iris Murdoch
32. A Theory of Justice by John Rawls
33. The Logic of Scientific Discovery by Karl Popper
34. The Social Contract by Jean-Jacques Rousseau
35. Being and Nothingness by Jean-Paul Sartre
36. The Black Swan: The Impact of the Highly Improbable by Nassim Nicholas Taleb
37. ​Ashtavakra Gita: The Ultimate Solace by Harsha
38. The Ego Trick: In Search Of The Self by Julian Baggini
39. The Principles of Morals and Legislation by Jeremy Bentham
40. Wholeness and the Implicate Order by David Bohm
41. Understanding Power: The Indispensable Chomsky by Noam Chomsky
42. On Liberty by John Stuart Mill
43. Fate by Ralph Waldo Emerson
44. Letters of Epicurus by Epicurus
45. Free Will by Sam Harris
46. Pragmatism by William James
47. Naming and Necessity by Saul A. Kripke
48. The Medium is the Massage by Marshall McLuhan
49. Justice: What's the Right Thing to Do? by Michael J. Sandel
50. The Life You Can Save: Acting Now to End World Poverty by Peter Singer
51. Living in the End Times by Slavoj Žižek

Source...

• 50 Psychology Classics by Tom Butler-Bowdon
• https://www.goodreads.com/list/show/72446.50_Psychology_Classics#646183