Her Secret -- Charlie Munger

Ok, so this post really should be called "His Secret," but regardless of gender, Charlie Munger is extremely sound of mind, even at age 83. From Morningstar.com:

With humor and clarity, Munger dispenses advice for living a well-examined life. Here are some nuggets of wisdom:
--Munger stated that many smart people handicapped themselves with "nuttiness." One example is being an "extreme ideologue," which is the equivalent of "having taken your brain and started pounding it with a hammer."
--Your life must focus on the "maximization of objectivity."
--"You must learn the method of learning."
--"It is totally unproductive to think the world has been unfair to you. Every tough stretch is an opportunity."
--"You can get away with more than you deserve in life by being slightly more rational."
--"I'm not going to complain about my age because without it, I'd be dead."