York, William Clark’s personal slave since childhood, “could not volunteer, or refuse, to go on the expedition.” That simple fact lies at the heart of this new title (Calkins Creek, 10/06) by Laurence Pringle and illustrated by Cornelius Van Wright and Ying-Hwa Hu.

At once elegant and packed with adventure, American Slave, American Hero centers the familiar story of the Lewis and Clark expedition around its sole black member, zeroing in on what’s known about his experiences in 1804-1806. Besides not having joined the expedition out of his own free will, York’s tale is distinct from those of other members in other ways. To the native peoples the expedition encountered, York was an object of fascination, his exotic coloring repeatedly earning him the honorific “Big Medicine.” And because Clark kept York illiterate, Pringle and other retellers of the team’s history must glean details of York’s life from the accounts of other members.

In that respect, York and his feelings — about being separated from his wife, about being allowed a vote in an expedition decision, about being honored by one group for the very reason he was enslaved by another — are unknowable. But that’s where Van Wright and Hu’s watercolors come in. They flesh out this brave man whose owner (who, by the way, comes off as something of a jerk) may well have assumed would be forgotten. With Pringle, they’ve seen to it that that won’t happen.