CQ Press 
Federal Regulatory Guide [PDF ebook] 

The Federal Regulatory Directory, Eighteenth Edition continues to offer a clear path through the maze of complex federal agencies and regulations, providing to-the-point analysis of regulations. Information-packed profiles of more than 100 federal agencies and departments detail the history, structure, purpose, actions, and key contacts for every regulatory agency in the U.S. government. Now updated with an improved searching structure, the Federal Regulatory Directory continues to be the leading reference for understanding federal regulations, providing a richer, more targeted exploration than is possible by cobbling together electronic and print sources.