I realise I have read a lot of classic novels but if you asked me to list classic non-fiction books, I wouldn't really know where to start.
What are the non-fic equivalents of Pride & Prejudice, Gatsby, To Kill A Mockingbird etc? The books you really should read before you die?
Having said I don't know where to start, I would recommend Aristotle's Nichomachean Ethics. It's surprising accessible in translation and it changed my view on friendship for the better, forever.