Upon arriving in Cambridge in July of 1775, George Washington immediately began identifying candidates to become the officers who he would trust to council him and carry out his orders. One selection would prove to be one of his best, a successful Boston store owner lacking any military experience. As a veracious reader he self-taught himself to become an expert in all matters of artillery, an expertise Washington would rely upon throughout war. Because of his irreplaceble role in battles such as the Siege of Boston, Trenton, and Yorktown, this major general ranks as one the war's most notable unsung heroes. Who was he?