The Associated Press

A new children's book aims to shed light on an overlooked member of Meriwether Lewis and William Clark's westward expedition, an exploration that began 200 years ago but whose story until recently was incompletely told.

York's Adventures With Lewis and Clark (HarperCollins; $17.99) by Rhoda Blumberg tells the story of Clark's slave, York, who was an integral part of the expedition.

The book, geared for ages 8 and up, includes excerpts of Clark's journals, which describe York's proficiency in dealing with American Indians, many of whom assumed that his dark color indicated spiritual powers and believed it marked him as a great person. York successfully traded with them for food to keep the expedition going and once risked his life to save Clark during a storm.

York, who as a slave was not allowed a last name, was roughly the same age as Clark and the two played together as children on Clark's family's Virginia plantation. In their early teens, York became Clark's manservant, and they were in their early 30s when they headed west with Lewis.

Despite his role in Lewis and Clark's expedition, York was unrecognized for his contributions during his life. Clark freed him more than 10 years after the expedition, and he set up a freight-hauling business and died in obscurity at an unknown date.

In honor of the 200-year anniversary of the start of the expedition, another book by Blumberg has been rereleased. The Incredible Journey of Lewis and Clark (HarperCollins; $12.99), an American Library Association notable book which also won a Golden Kite Award for nonfiction, is also for age 8 and up and gives a thorough account of the explorers' journey and the tribes they encountered along the way.