Secondary sources on Nietzsche:
Bernard Reginster, The Affirmation of Life: Nietzsche on Overcoming Nihilism
Bruce Ellis Benson, Pious Nietzsche: Decadence and Dionysian Faith
Maudemarie Clark, Nietzsche on Truth and Philosophy
Gianni Vattimo, Dialogue with Nietzsche, Nietzsche: An Introduction
Arthur Danto, Nietzsche as Philosopher
R. J. Hollingdale, Nietzsche: The Man and His Philosophy
Bernd Magnus (ed.), The Cambridge Companion to Nietzsche
Richard Schacht, Nietzsche
John Richardson, Nietzsche’s System, (ed.) Nietzsche
Henry Staten, Nietzsche’s Voice
Walter Kaufmann, Nietzsche: Philosopher, Psychologist, Antichrist
Alexander Nehamas, Nietzsche: Life as Literature
Robert C. Solomon, Living with Nietzsche: What the Great “Immoralist” Has to Teach Us, (ed.) Nietzsche: A Collection of Critical Essays
Robert C. Solomon & Kathleen Higgins, What Nietzsche Really Said, (eds.) Reading Nietzsche
Julian Young, Nietzsche’s Philosophy of Art, Nietzsche’s Philosophy of Religion
Gilles Deleuze, Nietzsche and Philosophy
Michael Tanner, Nietzsche: A Very Short Introduction