Critical Thinking is a discipline that provides the means to distinguish good from bad arguments. In doing so, it draws on the contributions of other disciplines such as logic, psychology, argumentation, and probability theory. By exploiting and developing our ability to reason, it makes us understand why certain reasoning patterns are correct and others are not. This book is an introduction to Critical Thinking, to the role that reasoning plays in concrete contexts and to the forms it assumes in different fields. The first part of the book explains what an argument is and what types of argument exist; the second deals with deductive arguments, with particular attention to arguments involving conditionals and counterfactuals; the third takes into consideration some non-deductive arguments, such as statistical reasoning, reasoning with probabilities, reasoning with explanatory hypotheses, inference to the best explanation, and reasoning by analogy. The volume also clarifies why it is important to think well. Recognizing and providing good arguments helps us have a better understanding of the issues we face when making choices and interacting with others.