Here are some books we found useful. They are in order, beginning with the most relevant.

 

Fiction:

Works by Herman Hesse: We recommend Siddhartha, Demian, and Narcissus and Goldmund. Hesse bridges eastern and western philosophical thought. His novels show individual spiritual journeys.

Works by Milan Kundera: We recommend The Unbearable Lightness of Being, Immortality and The Joke. Kundera explores themes of identity and history as a continual return. See our full review of The Unbearable Lightness of Being.

The Fountainhead, Ayn Rand: Love her or hate her, Ayn Rand will change the way you think about society and your place in it.

The Little Prince, Antoine de Saint-Exupéry: The Little Prince shows what people cling to and how it's unhelpful and advocates keeping yourself open to relationships, even though it's hard sometimes.

Ficciones by Jorge Luis Borges: We recommend The Library of Babel and Funes the Memorious. Borges plays with our notions infinity in his novels.

The Complete Stories, Franz Kafka: Alienation, persecution, futility; Kafka's works are full of existential themes, magical realism and anarchy. See Laura's essay on the story "An Old Manuscript".

Gould's Book of Fish, Richard Flanagan: Playing with reality and stories, Flanagan weaves a wild story about creation and reality.

The Mind Parasites, Colin Wilson: Fantastic story about the frontiers of the mind. Lots of real philosophy and anthropology mixed it.

The Hitchhiker's Guide to the Galaxy, Douglas Adams: The modern day Alice and Wonderland, The Hitchhiker's Guide is a cult classic full of funny adventures in an infinite universe.

Alice in Wonderland/Through the Looking Glass, Lewis Carroll: A story about questioning reality and contemplating the riddle of life. There's lots of great math allusions too. The annotated version we've linked to is especially interesting.

Works by Fyodor Dostoevsky: We recommend Crime and Punishment and The Brothers Karamazov. Dostoevsky's novels explore psychology and pre-existentialist thought.

Jonathan Livingston Seagull, Richard Bach: A short novel about following your own path to self-perfection.

Flatland, Edwin Abbott Abbott: Not only a commentary on the victorian class system, but an exploration of other dimensions.

Non Fiction

Tao Te Ching: The basic text of Taoism, about being one with the natural flow of the universe.

The Spontaneous Fulfillment of Desire, Deepak Chopra: Practical exercises to help you connect with your higher self. Learn about coincidences!

Works of Friedrich Nietzsche: Philosophy about how to look beyond the normal good/evil dichotomy. Not recommended for depressed people. Also see our Laura's article, and Emily's essay on Nietzsche.

Works of Rudolf Steiner: Steiner is one of the founders of Anthroposophy, his works outline the nature of the universe, other dimensions and other beings. See our related review.

Saving the Appearances, Owen Barfield: History of the evolution of consciousness.

The 4-Hour Workweek, Timothy Ferriss: Empowering you to spend your limited time on earth doing what makes you happiest.

Works of C. S. Lewis: Lewis is a Christian writer. We aren't endorsing Christianity, but his works have good insights on Christianity and spirituality in general.

Einstein's Dreams, Alan Lightman: An inventive, playful book which bridges the gap between science and art. See our article.

Unancestral Voice, Owen Barfield: The book reexamines Plato and recreates his dialogue to focus on modern philosophical problems of reality and ways of knowing. See our full review.