Who is Private John Colter from The Journals of Lewis and Clark and what is their importance?

Private John Colter was a permanent member of the Corps' expedition from the beginning. He was an excellent hunter, as well as a courageous explorer. In November 1805, he was part of the team that traveled alongside William Clark for nine miles, from Camp Disappointment to the Pacific coast. He was discharged from the Corps before it reached St. Louis, on his own request. He later joined with other trappers, and he eventually joined the Manuel Lisa Company. In 1809, while trapping in Blackfeet country with John Potts, he managed to outrun the Indians who were after them. He escaped, but his partner was killed. Prior to the 1814 publication of the Journals, Colter helped Clark draw a more precise map of the American West by providing him with detailed descriptions of the mountain country. He was the first white man to set foot in Yellowstone.