Overall, this is not a bad book. In fact, I can see how it can be quite helpful for some. However, I must admit I'm not impressed by this book and would certainly not use it to teach a logic class.
This book provides generous background information and explanation to the terms, concepts, rules, methods, etc. contained within. It also comes with a CD-Rom with helpufl information that guides you through the learning process. With this book, it is possible to submit your work to the "gradegrinder" grading service which will give you feedback on the submitted problems (Generally it tells you which line the mistake is made on or the type of mistake made.) It also uses a geometry based program which helps students understand what predicates are and how the function as variable modifiers. This can be quite helpful for the struggling student, students who do not self-check well, and (potentially) students with poor logic teachers. It covers sentential/propositional logic as well as predicate logic.
Having been exposed to other logic systems, most notibly that used by Allen and Hand in "Logic Primer." ( Logic Primer - 2nd Edition ) I find the system in LPL tedious, time consuming, and unnecessarily difficult. The logical operators were easier to read, to begin with. Most importantly, as one progressed through the text more derrived rules were available for use during proofs. (For people who are not familiar with logic, try to imagine making change with only pennies and ones. You can do it, but it is frustrating and hardly the fastest way. This is what the LPL book is like. "Logic Primer" is like having every denomination between pennies and twenties. - Having more rules is simply having more tools and options to work with.) I also had problems with the software. Answers must be entered near-perfectly and it is not very user friendly. It was difficult to enter commands and find buttons. Even if things were going smoothly it would still make my computer (which runs Windows Vista) crash continuously. My classmates who used Macs had problems, but they were different than those of us who used PCs. Although it requires a good professor, I prefer a more flexible system that allows students to be more creative in their proofs and does not bog them down in tedium.
Lastly, I couldn't stand how the LPL system forced usuers to discharge assumptions in the reverse order from which they were assumed. (A1, A2, A3 must be used in order of A3, A2, A1) It does this by forcing the user to make numerous sub-proofs which, using the other system, could be avoided by simply citing a derived rule.