Toni Morrison's first two books—"The Bluest Eye" with the purity of its terrors and "Sula" with its dense poetry and the depth of its probing into a small circle of lives—were strong novels. Yet, firm as they both were in achievement and promise, they didn't fully forecast her new book, "Song of Solomon." Here the depths of the younger work are still evident, but now they thrust outward, into wider fields, for longer intervals, encompassing many more lives. The result is a long prose tale that surveys nearly a century of American history as it impinges upon a single family. In short, this is a full novel—rich, slow enough to impress itself upon us like a love affair or a sickness….

"Song of Solomon" isn't, however, cast in the basically realistic mode of most family novels. In fact, its negotiations with fantasy, fable, song and...