This book from the late 70's definitely has an agenda (namely, toilet "learning" -- NOT "training!!" -- must be child-directed and trying to do it one day is cruel. Whatever). The intro part, which was mostly a history and criticism of toilet training over the past 100 years, was interesting but not particularly helpful as far as usable techniques go. As for the picture book at the end - maybe it would help some kids, but mine didn't need it.
Beginning to teach Lillian about the toilet. What fun. This book includes "interesting" and somewhat shocking history about potty training. Of course, there's all the psychology and physiology about using the toilet too. Ugh!