"You are either a Mildred Walker enthusiast," as the Philadelphia Inquirer once declared, "or you are missing one of the best writers on the American scene." As Mildred Walker's daughter, Ripley Hugo was in the latter category. This biography of the author of thirteen celebrated novels is also Hugo's search for the writing life of a mother known to her children as a socially correct middle-class doctor's wife rather than as the ambitious, imaginative, often struggling novelist she was as well.   Drawing on family memories, letters, diaries, reviews, and, in particular, the notebooks that Mildred Walker (1905-1998) kept for each novel, Hugo fashions an absorbing account of how her mother's characters emerged in the landscapes that she visited again and again: Vermont, the Midwest, and, most frequently, Montana, the setting for the classic Winter Wheat. Alongside this developing picture of a writer at work--shaping her contribution to western America's literary history over half a century--Hugo shows us the proper mother and social creature as carefully and consciously crafted; between the two lovingly detailed portrayals, we glimpse the depths of a life thus divided.