Harriet Ryegate, the proper daughter of Massachusetts Puritans, is the first white woman to go far into the wilderness beyond the upper Missouri. With her husband, a Baptist minister, she seeks to convert the Blackfoot Indians to Christianity. But it is the Ryegates who are changed by their "journey into strangeness." Marcus Ryegate returns to Massachusetts obsessed by a beautiful Indian woman. For sermonizing about her, he pays a heavy price.   Harriet, one of Mildred Walker's most fully realized characters, writes in her journal about "the effect of the Wilderness on civilized persons who are accustomed to live in the world of words." If a Lion Could Talk reveals the tragic lack of communication that stretches from Massachusetts to Missouri and beyond in the years before the Civil War--and the appalling heart of darkness that is close to home.