By Gretchen Rubin

2011 Happiness Challenge: For those of you following the 2011 Happiness Project Challenge, to make 2011 a happier year -- and even if you haven’t officially signed up for the challenge -- welcome!

For the last month of this year, instead of tackling a theme, I'm going to discuss a question: What is the key to happiness? That's a question that can be answered in different ways, depending on what framework you use to address the issue of happiness. The resolution for each week will reflect that week's answer.

Last week’s answer was to Cultivate strong relationships. This week’s answer is to Know yourself.

Know yourself.

It's a little hard to see what I'm holding in my hand. That's... More...