I am the author of three logic and critical thinking books, which are published by Classical Academic Press:
Argument Builder
Discovery of Deduction (co-author)
Everyday Debate
You can find these books at Classical Academic PressĀ here.
And you can also order them from Amazon:
Everyday Debate (I recommend starting with this one.)
Argument Builder
Discovery of Deduction
You can read more about the importance of critical thinking here:
Five Ways to Think more Critically and How it Benefits You
I also recently published an article on playfulness with Tiny Buddha, which you can read here:
How I Overcame the Stress of Perfectionism by Learning to Play Again
And here is a recent article I wrote for Tiny Buddha on Mindfulness:
How Mindfulness Helped Me Become My Own Best Friend