Open Culture: Three Huge Volumes of Stoic Writings by Seneca Now Free Online, Thanks to Tim Ferriss.

At its core, it teaches you how to separate what you can control from what you cannot, and it trains you to focus exclusively on the former.

Ferriss can overreach his basic circle of expertise, but he keeps pushing his boundaries openly ... and I surely do appreciate it. His endeavors haven't enriched me financially, but very much so personally. Stoicism for the win!