A logical fallacy is an error in reasoning that renders and argument invalid. Logical fallacies are often categorized as irrelevant, ambiguous, or presumptuous, and can often be identified because they have insufficient evidence to support their claim.
Use these resources to learn more about different types of logical fallacies, so you can avoid them in your arguments and recognize them in the arguments of others.
The Thinker's Guide to Fallacies by 
Logic and Contemporary Rhetoric by 