O*NET OnLine has detailed descriptions of the world of work for use by job seekers, workforce development and HR professionals, students, researchers, and more.
Published by the U.S. Department of Labor's Bureau of Labor Statistics, this online tool offers information on hundreds of occupations and is updated yearly. It's a good place to go for general information on a wide-range of careers and vocations.
This is the complete Dictionary of Occupational Titles (DOT) revised fourth edition, as supplied electronically by the US Dept. of Labor, provided, as a public service, by ITA, makers of DOT and O*Net for Windows.