Over the past century, the U.S. has developed a deep, diverse pool of skilled, productive and well-paid service providers.

The first few months of 2008 saw crude oil prices breach one barrier after another. They topped $100 a barrel for the first time on Feb. 19, then rose past $103.76 about two weeks later, surpassing the previous inflation-adjusted peak, established in 1980. In April and early May, oil prices...