It is important to be forewarned that this is not a good text for an introductory logic class. I have taught classes using several other texts, and, although they had their flaws, the Forbes' text has flaws that are almost unsurmountable for the typical lower-division college student. The explanations, though creative,are not clear enough, and the flow of topics is out of sorts. For example, the exercises which accompany the sections start out too difficult to be any aid in helping the introductory student grasp the techniques. In short, for upper-division courses or for people who already have a logic background, this is an interesting book and might be worth a look, but it fails miserably as an introductory text.