Critical thinking is discussed in this book in relation to the ability to read and criticize explanatory texts in physics. It is argued that it is valuable but insufficient to know the general principles of critical analysis of texts, such as source control or knowledge of the main cognitive biases. We set out the objective of the book, that is, to contribute mainly to an education of critical thinking in physics. The value of physics as a favourable ground for the development of critical analysis and possible obstacles in this respect are discussed. We examine the role of metacognition. We also point out the existence of teaching rituals in physics teaching that hinder our critical lucidity. More broadly, we recognize the intrinsic difficulty of conducting valid reasoning in physics, especially given the multiplicity of variables involved. Finally, we emphasize that the purpose of this book is to highlight how certain tools can help us to successfully combine critical thinking with better understanding. [For the complete volume, "Developing Critical Thinking in Physics: The Apprenticeship of Critique. Contributions from Science Education Research. Volume 7," see ED615688.]