A whole book on it? Yes, and the advice is sound and relaxed, presenting professional findings in everyday language. Mack scans past writings on the subject, rightly dismisses the toilet-train-in-a-day school as ""rat psychology,"" and discusses what parents must know about physiological mechanisms, maturation cycles, household patterns--girls generally learn faster, training pants help prevent accidents. The second part is a picture book explaining the pertinent facts to children--a thoughtful complement. But Mack's well-developed idea--a book for parents and children to share--is ill served by George Phillips' cartoon-like drawings which vary from just adequate to ambiguous and rarely represent the text in the most instructive manner. Parents wondering how to begin this needlessly charged phase can benefit from the informative exposition in the first part and take a cue from Mack's phrasing in the second, but they ought to skip the pictorial presentation altogether.