The real ones, via Plato
“The unexamined life is not worth living.” Plato's Apology (38a), at his trial, moments after refusing to trade philosophy for his life. As close to a verified Socrates sentence as antiquity offers, and still the best one-line job description the field has. The gadfly: also from the Apology, his self-description as the stinging insect keeping the lazy horse of Athens awake; they killed the gadfly, which rather proved the point.
The paraphrases behaving as quotes
“I know that I know nothing.” The neat version appears nowhere; in the Apology he says he neither knows nor thinks he knows, unlike the experts who don't know but think they do. The compressed slogan is fair to the idea and false as a citation, the classic smoothing pattern. “I am a citizen of the world.” Attributed by Plutarch centuries later, and also claimed for Diogenes with better sourcing; enjoy it as tradition, not transcript.
The two great fakes
“Be kind, for everyone you meet is fighting a hard battle.” Not Socrates, not ancient: it descends from Scottish author Ian Maclaren, published 1897, and grew a toga on the internet. “The secret of change is to focus all of your energy not on fighting the old, but on building the new.” The best fake-quote story on our shelf: it's from Way of the Peaceful Warrior (1980) by Dan Millman, spoken by a fictional gas-station sage whom Millman named Socrates. A character's name became a citation, and the internet did the rest.
Why the mess is the lesson
Socrates is the patron saint of checking claims, and his own quote page fails the check constantly; he'd have enjoyed that, then cross-examined it. His actual method (question the confident, define your terms, follow the argument) survives intact in Plato's dialogues, in the conversational-philosophy shelf, and one page at a time in 365 Days of Philosophy, where he opens the whole chronological year (★4.5 across 253 Amazon ratings). The beginner shelf is the free door.
Common questions
Did Socrates write any books?
None; he taught by conversation and wrote nothing. Everything comes through students, mainly Plato (whose dialogues star him) and Xenophon, which is why every 'Socrates quote' is really a citation of someone else's record.
Did Socrates say 'the unexamined life is not worth living'?
Yes, per Plato's Apology (38a), the account of his trial written by an eyewitness student. It's the best-sourced Socrates line in existence.
Did Socrates say 'be kind, for everyone you meet is fighting a hard battle'?
No; the line descends from Ian Maclaren, a Scottish author writing in 1897. It's kind, it's wise, and it's twenty-three centuries too late to be Socrates.
Did Socrates say 'the secret of change is to focus your energy on building the new'?
No: it's dialogue from Dan Millman's 1980 book Way of the Peaceful Warrior, spoken by a fictional mentor character named Socrates. The character's name migrated onto the quote, creating philosophy's funniest misattribution.