Reddit reviews The Rebel: An Essay on Man in Revolt

Existentialism and Human Emotions, by Sartre, is only 96 pages and quite an easy read. {ISBN-13: 978-0806509020} Existentialism and the Philosophical Tradition, [Raymond], gives a broad selection of thinkers throughout history, but it is pricey. {ISBN-13: 978-0132957755} Another approach would be texts that are not strictly philosophical yet present some existential points such as: The Plague, The Stranger, and The Rebel, all by Camus, Nausea by Sartre, Notes From Underground, by Dostoevsky, or Waiting For Godot by Beckett

Honestly, I'm far more into sociology and philosophy than economics so most of my suggestions will be based on those!

I couldn't recommend Camus' The Rebel or
The Myth Of Sisyphous

Ooooh or Jean-Paul Sartre's (or as you may know him: one of the leftists who tried to abolish the age of consent) The Wall or
Existenialism Is A Humanism

These are the kinds of works that inform my worldview more than any other, and I believe them to be great jumping off points into abusrdism and existentialism respectively (though Existenialism Is A Humanism could also be replaced by a much stronger work of his, Being and Nothingness )

• Minsky, Marvin - The Society of Mind
  
• Minsky, Marvin - The Emotion Machine
  
• Coetzee, John Maxwell - Summertime
  
• Hawking, Stephen & Mlodinow, Leonard - The Grand Design
  
• Camus, Albert - The Rebel

Never justified on a moral scale. It is rather hard to explain in forum context without going into lengthy philosophical discussions. I would just recommend reading 'The Rebel' by Albert Camus.