Frankly Existential

Medieval Philosophy
Selected Writings – St. Thomas Aquinas
Confessions – St. Augustine

Modern Philosophy
Grounding for the Metaphysics of Morals – Immanuel Kant
Meditations on First Philosophy – Renee Descartes
The Myth of Sisyphus – Albert Camus

Psychology / Psychiatry
Dopamine Nation – Dr. Anna Lembke
The Boy Who Was Raised as a Dog – Dr. Bruce Perry and Maia Szalavitz
The Undiscovered Self – Carl G. Jung

Political Philosophy
For A New Liberty – Murray N. Rothbard
On Liberty, Utilitarianism, and Other Essays – John Stuart Mill