I absolutely love logic, but this book was not in depth enough and it was wrong. For example, it said that a rule of syllogism validity was that you can only have three terms, but if you have more than three terms, it isn't even a syllogism! So having more than three terms can't make a syllogism invalid if when it has more than three it is by definition not even a syllogism! There was this same problem with the rule that you can't have middle terms in the conclusion. It also often did not put catergorical statements into standard catergorical form. If you want to learn logic, definitely don't read this, go read the Challenge B introductory logic(informal logic, like this book) and advanced logic(formal logic) by canon logic.