The authors explain not just what is available (in terms of X and Motif programming) but also that it is intended for and when it should be used. Part one, the Motif toolkit, covers the toolkit itself; part two concentrates on some of the underlying mechanisms of Xt and Xlib, particularly those which provide functionality which Motif doesn't; and part three looks at Motif from above, from the point of view of the application.
