On the topic of crucial books that everyone ought to read, The Count of Monte Cristo contains an interesting passage. In Chapter 16, when Dantes is in prison and speaking with Abbe Faria, his fellow prisoner, Faria makes the following statement.
“I had nearly five thousand volumes in my library at Rome; but after reading them over many times, I found out that with one hundred and fifty well-chosen books a man possesses, if not a complete summary of all human knowledge, at least all that a man need really know. I devoted three years of my life to reading and studying these one hundred and fifty volumes, till I knew them nearly by heart; so that since I have been in prison, a very slight effort of memory has enabled me to recall their contents as readily as though the pages were open before me. I could recite you the whole of Thucydides, Xenophon, Plutarch, Titus Livius, Tacitus, Strada, Jornandes, Dante, Montaigne, Shakespeare, Spinoza, Machiavelli, and Bossuet. I name only the most important.”
I have always wondered what the full list of 150 books would have been. I doubt that Dumas actually had such a list in mind, but the idea is still intriguing and probably what originally got me thinking about the idea of “what everyone ought to read”.