Start with high-confidence modern philosophy books, then narrow by subgenre or adjacent topics.
The Seventeenth Century
Andrew Lossky
Phenomenology of Spirit
G. W. F. Hegel, A. V. Miller
Situating Existentialism
Jonathan Judaken, Robert Bernasconi
Basic Writings of Existentialism
Gordon Marino
History of Western Philosophy
Bertrand Russell
Humanly Possible
Sarah Bakewell
Existential America
George Cotkin
Escape From Reason
Francis A. Schaeffer
Ideas Against Ideocracy
Mikhail Epstein
A Short History of Decay
E. M. Cioran, Richard Howard
Collected Essays of Arthur Schopenhauer
Arthur Schopenhauer
Principles of Philosophy
René Descartes
Nietzsche
Stefan Zweig, Will Stone
Existentialism
Thomas E. Wartenberg
Dialogues Concerning Natural Religion
David Hume
The Critique of Judgement
Immanuel Kant
Critique of Practical Reason
Genealogy of Morals
Friedrich Nietzsche
