York was the slave William Clark took with him on the Lewis and Clark expedition. He carried, cooked, scouted, and he saved the expedition on several occasions from hostile natives who proved fascinated by the black "bear-man." York couldn't read or write, so what we know of him largely comes from the journals kept by Lewis and Clark and other white members of the expedition. He is also depicted in paintings serving to commemorate the event.
In this poetic journal, Frank X. Walker gives voice to York, presenting him as a thinking-being, capable of reflecting on his plight as a slave, as a man who misses his wife and family, as an observer of human nature, and as a scout who anticipates danger, confronts it, and whose resourcefulness and improvisations help forge the future of a nation (not to mention save the necks of his white colleagues.) York was eventually freed by Clark, many years later, but through Walker's voice, we come to appreciate how much he yearns for that freedom and how the expedition provides a sense of freedom that gives York hope for a future beyond slavery. This is a remarkable work- both poetry, biography, and historical fiction, and lovely to read though meant for an older audience. (I wish it were illustrated, in fact.)