Dashiell Hammett was born in St. Marys County, Maryland, in 1894.  HE grew up in Philadelphia and Baltimore.  He left school at the age of fourteen and held several kinds of jobs thereafter—messenger boy, newsboy, clerk, timekeeper, yardman, machine operator, and stevedore.  He finally became an operative for Pinkerton's Detective Agency.
   World War I, in which he served as a sergeant, interrupted his sleuthing and injured his health.  When he was finally discharged from the last of several hospitals, he resumed detective work.  Subsequently he turned to writing, and in the late 1920s he became the unquestioned master of detective-story fiction in America. During World War II, Mr. Hammett again served as a sergeant in the army, this time for more than two years, most of which he spent in the Aleutians.  He died in 1961.