When Robert F. Peary claimed discovery of the North Pole on April 6, 1909, the only other American to stand beside him was a black man, Matthew A. Henson. A native of Charles County, Maryland, Henson accompanied Peary on eight Arctic journeys between 1891 and 1909. His skill in interpreting the language of the North Greenland Eskimos, in building boats and repairing sledges, and in driving dog teams was essential to the ultimate success of the admiral, who wrote, "I can't get along without him." Yet Henson was for the most part ignored, even by Peary, after that historic expedition.   A Black Explorer at the North Pole reminds the reader that where Peary went so did Henson--often one step ahead as a troubleshooter. Drawing largely on his diaries, Henson describes the voyage of the steamer Roosevelt to Cape Sheridan on Ellesmere Island in the Canadian Arctic and the four-hundred-mile trek by dogsled over treacherous ice to the top of the world.   Susan A. Kaplan, in her introduction to the Bison Book edition, discusses Henson's accomplishments and the current controversy surrounding Peary's claim to discovery of the North Pole.