The U.S. Army was founded on June 14, 1775, when the Continental Congress authorized enlistment of riflemen to serve the United Colonies for one year. For more on the history of the U.S. Army birthday, click here: the Army birthday.
Directory publishing is a specialized genre within the publishing industry. These publishers produce mailing lists, telephone books, and other types of directories. With the advent of the Internet, many of these directories are now online.
Agents are as diversified as publishers. Know what kind of book you're writing (i.e., fiction--children's, genre or literary), or non-fiction (i.e., a biography, a math book, a cookbook, a self-help book, etc.) and then do your research to find out which agents rep that type of title.