[prhps]

Nothing by wittgenstein qualifies as "one of the most accessible pieces of philosophy ever written". If you believe this, you probably didn't understand what you were reading. If you want accessible, then I'd start with the pre-socratics.

[cortesoft]

Marcus Aurelius is very accessible, and feels very modern.

[jibbit]

Well what a mess this comment page is! The Tractatus is certainly not accessible, but the later Wittgenstein easily qualifies as the most accessible philosophy ever written.