1. "Sophie's World" by Jostein Gaarder: A philosophical novel that takes the reader on a journey through the history of philosophy, introducing key concepts and thinkers in an engaging manner.
2. "The Republic" by Plato: A classic work that explores the nature of justice, the ideal society, and the role of the philosopher-king.
3. "Nicomachean Ethics" by Aristotle: Aristotle's examination of ethics, focusing on virtue and the pursuit of happiness (eudaimonia), which remains influential in ethical thought.
4. "Meditations" by Marcus Aurelius: A collection of personal writings and reflections by the Roman emperor and Stoic philosopher, providing insights into Stoic philosophy and the pursuit of virtue.
5. "The Critique of Pure Reason" by Immanuel Kant: A seminal work in epistemology, Kant's critique examines the limits of human knowledge and the nature of reality.
6. "Thus Spoke Zarathustra" by Friedrich Nietzsche: Nietzsche's exploration of existential themes such as the will to power, the Übermensch (Superman), and the eternal recurrence.
7. "Being and Nothingness" by Jean-Paul Sartre: Sartre's existentialist treatise on the nature of being, consciousness, and freedom.
8. "The Stranger" by Albert Camus: A novel that delves into the themes of existentialism, absurdity, and the search for meaning.
9. "The Structure of Scientific Revolutions" by Thomas Kuhn: A pioneering work in the philosophy of science that examines how scientific knowledge evolves through paradigm shifts.
10. "The Problems of Philosophy" by Bertrand Russell: Russell's concise and accessible introduction to philosophical topics, covering a range of issues from metaphysics to ethics.