James Duncan Phillips, second son of the Honorable Stephen Henry and Margaret (Duncan) Phillips, was born in San Francisco, California in 1876. He attended Harvard College and graduated in 1897 magna cum laude. Less than one year later he joined the publishing firm of Houghton Mifflin Company and worked there until his retirement in 1941.

Phillips married Nannie J. Borden of Fall River, Massachusetts in 1907, with the wedding taking place in England. They traveled widely both before and after marriage.

Due to a serious heart attack in 1936, his business activities became limited. He filled his time with historical research and writing. Numerous articles and books, most of which were about Salem's "Great Age of Sail," were published during the last twenty years of his life.

Phillips was a captain in the Massachusetts State Guard and this collection consists of his material relating to the 15th Infantry Regiment, a Machine Gun Company. The history of the State Guard begins in 1863, when the legislature authorized the formation of a State Guard that served through 1866 before being disbanded. Reorganized in 1898 as the Massachusetts Provisional Militia, it served during the Spanish American War before being disbanded in 1899. In April 1917, the legislature again called for the formation of the Massachusetts Home Guard and the name was changed to the Massachusetts State Guard.

During World War II the organization was activated and served until February 1947 when it was deactivated. The Massachusetts State Guard was reactivated on a statewide basis in 1966. Since that time, it has undergone several structural and organizational changes to reflect its changing mission. In June 1994, the State Guard was renamed the Massachusetts Military Reserve.

Since September 11, 2001 and the conflicts in Afghanistan and Iraq, the needs of the National Guard have changed. Consequently, The Adjutant General ordered the reorganization of the Massachusetts Military Reserve into the Massachusetts State Guard to assist in meeting the needs of the Massachusetts Army and Air National Guard.