Who is Leatherstocking?

Leatherstocking is one of the many nicknames of Natty Bumppo, the main character in James Fenimore Cooper's five Leatherstocking novels. We learn in the novel The Pioneers that the deer or buckskin breeches that Bumppo wears, which are like what the Native Americans wear but unusual for Europeans, gained him the nickname Leatherstocking among the white settlers:

On his feet were deer-skin moccasins, ornamented with porcupines' quills, after the manner of the Indians, and his limbs were guarded with long leggings of the same material as the moccasins, which, gartering over the knees of his tarnished buckskin breeches, had obtained for him among the settlers the nickname of Leather-Stocking.

Natty Bumppo is of European descent, but he was raised among the Delaware Indians. The Moravians, a Christian group, educated him. He has arrived in the wilderness and among the Iroquois and Mohawks ahead of many of the other settlers. He respects the Native Americans, as is natural for someone brought up among them, and has learned from their ways, many of which he has adopted. The Native Americans also respect him and have given him such names as Pathfinder and Hawkeye. He is the foster brother of Chingachgook, a Mohican chief.
Bumppo, in many ways an idealized character, is a bridge between European and Native American culture. He represents ways the European settlers might have come to live peacefully among the Indians and their lands. Like the Native Americans, he respects nature and never kills more animals than he needs to eat. He lives simply and close to earth. Unfortunately, as more and more white settlers pour in and begin wholesale killing of the wildlife--such as dynamiting hundreds of fish from the water--Bumpoo mourns the loss of Native American culture and its connection and reverence for nature. As the Leatherstocking books end, Bumppo head farther west, as he can not accept all the ways of European civilization.