The three-dimensional world of sculpture comes alive in ''this museum without walls,'' the sixth thought-provoking art book from Bob Raczka. As curator of this exhibition, Raczka focuses on sculpture from the twentieth century, arranging alphabetically from a (in the form of an Arrow) to Z (in the shape zig-zags). He not only points out different styles of sculpture such as abstract, kinetic, and relief, but also covers the variety of materials--stone,...