What’s the best super thin book you’ve ever read? (Under 100 pages)

I’m looking for recommendations for short but powerful books (ideally under 100 pages).

So far I’ve read:
• Siddhartha
• The Little Prince
• The Stranger
• The Alchemist
• Of Mice and Men
• Animal Farm

Any similar short reads you’d recommend? Fiction, philosophy, or classics are all welcome.