I had the good fortune last week of listening to a father-daughter writing team from Atlanta that has a lot to say about how Americans can live more fulfilling lives and at the same time can help others.

Kevin and Hannah Salwen are the authors of The Power of Half — a book that’s generating national buzz for its appeal simply to cut something in your life in half and to use the savings to help others.

A couple of weeks ago, Parade ran an excerpt. Then, it was the subject of New York Times column by Nicholas Kristrof. The Selwans also have been featured on NBC’s Today show, in the LA Times and on Belief.net.

I happened to see  Kevin and Hannah speak last week at TEDxAtlanta (organized by the Atlanta communications firm Unboundary) where the theme was “re:purpose.”

Three throughtful architects talked at TEDx about repurposing buildings and cities to make them sustainable. A blogger/publisher spoke about how Africans are repurposing technology to be more useful in developing nations. And a New York City nonprofit entrepreneur outlined how her organization, Goods for Good, is repurposing discarded materials for use by community organizations in Malawi and Haiti.

The Salwens fit right in. Their entire family, including mom and brother, was inspired to repurpose their lives after Kevin and Hannah stopped for a red light at the corner of the Buford Highway Connector off-ramp and Spring Street in Midtown. Hannah noticed the discrepancy between a man in a black Mercedes convertible in the lane next to them and a homeless man begging on the corner.

“Dad, if that man had a less nice car, that man there could have a meal,” Kevin recalls Hannah saying.

“Um, yeah,” Kevin answered. “But, you know, if we had a less nice car, he could have a meal.”

That conversation started the Salwens on the path toward their first “half project.” The book chronicles their decision to sell their Ansley Park home and to buy another for half the price, and then the painstaking process they followed to figure out the best way to use the leftover $800,000 to help people.

Along the way, they discovered for themselves something that fits very neatly into a familiar environmental message: we can enjoy more fulfilling lives while we’re using less resources. In the smaller house, family members began to enjoy more activities together. And the adventure of doing something for the greater good — ultimately, through the New York-based Hunger Project, for villagers in Ghana — made them closer still.

Kristof wrote this about the inherent power of giving in his Jan. 24 column on The Power of Half:

In a column a week ago, I described neurological evidence from brain scans that altruism lights up parts of the brain normally associated with more primal gratifications such as food and sex. The Salwens’ experience confirms the selfish pleasures of selflessness.

Kevin and Hannah’s point isn’t that every family ought to half-size their home. But they do encourage people to start their own “half projects,” which they insist could entail giving up half of even a small, non-material thing, like watching television.

That giving does the giver good is an old message, increasingly reinforced by biological research of the sort Kristof mentioned. But Kevin and Hannah seem to have struck a chord with the simple way they’ve frame that message. “Why ‘half?’” Kevin asks in the book. “Because it’s measurable,” he answers. Half “provides us with a metric to live with, a way to set a standard to push us to achieve.”

The Power of Half also is the sort of short, practical book that can take off as a popular rallying cry. It’s pithy well-written narrative (Kevin used to write for the Wall Street Journal) interspersed with how-to passages.

There is, of course, the argument that some people might not be in a giving mood nowadays; if your salary drops by half before you start your half-project, you could end up thinking about the “pain of a quarter” rather than “the power of half.”

On the other hand, downsizing may be a prevailing social theme of a new decade, just as supersizing was in the decade that just ended. If it is, the Salwens’ little book could become the manifesto for a more responsible and satifying relationship with the material world.

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2. Georgia Power moves a wee bit away from coal
3. A decade later, Portland’s better off than ATL
4. TEDx: Re-purposing Atlanta
5. Ga. Power nuke plan panned by PSC staff