The 4-Hour Body, Ferriss' treatise on using tracking to lose weight, maximize efficiency and "become superhuman, " shot to the top of the New York Times bestseller list in January.

FORBES: Magazine Article

Despite their safety risks, they are increasingly attractive to aircraft makers as a way to cut weight and thus improve fuel efficiency.

NPR: FAA Approves Resumption Of Boeing 787 Flights

Given today's materials and know-how, automotive engineers reckon a 10% reduction in vehicle weight yields a 6% improvement in efficiency.

ECONOMIST: Tech.view: Unbearable lightness? | The