In order:

Joseph Glanville, The Vanity of Dogmatizing; quoted by Matthew Arnold by way of preface to The Scholar-Gypsy.

Christopher Marlowe, The Tragicall Historie of Doctor Faustus.

William Blake.

Leonard Cohen.

Dante.

Gosse, The Life of Doctor Donne.

Dennis Overbye, Einstein In Love.

Izzak Walton, The Life of Doctor Donne.

Grothendieck.

Hesse, Steppenwolf.

Herman Melville, Moby Dick.

John Donne.

Voltaire.

Plato, Symposium.

Wittgenstein, Letters.

Pasternak, Doctor Zhivago.

Unknown but apparently respected academic commentator of the fifteenth century.

Rostand, Cyrano de Bergerac.

Augustine.

Nietzsche, Beyond Good and Evil, paragraph 29. Kaufmann translation.

Note of early 1974.

Boswell, The Life of Samuel Johnson.

Hesse, Steppenwolf.

Various sources.

Dostoevsky, The Idiot.

Note of 1979.

Plato, Symposium.

Kierkegaard, Either/Or.

Mary Shelley, Frankenstein.

Edward E. Smith, The Skylark of Space.

Shakespeare.

Copernicus.

Edward E. Smith, Skylark Three.

Note of 1973.

Note of 1973.

Arthur Conan Doyle, “The Adventure of the Empty House”.

Prologue to letter of 1974.

Letter of 1974.

Note of 1973.

Kurd Lasswitz, Auf Zwei Planeten.

Boswell.

Donne.

Wallace Shawn, My Dinner With Andre.

Boswell.

Photographs by Mark Lankton.

Richard Feynman, “Space-Time Approach to Non-Relativistic Quantum Mechanics”.

W.H. Auden, Phi Beta Kappa poem, Harvard, 1946.

Burton, Anatomy of Melancholy.

Keynes, “Newton the man”.

Fragment of 1974.

Smith, Skylark Duquesne.

Foucault, Madness and Civilization.

Bunyan, The Pilgrim’s Progress.

Einstein, final paragraph of The Meaning of Relativity.

Harlan Ellison, A Boy and his Dog.

Matthew Arnold, The Scholar-Gypsy.

Fragment of 1979.