This is a text intended for use by undergraduates in critical thinking classes, and for lay readers who want to learn that subject. In the first part of the text, basic logical concepts are covered. These include statements, questions, answers, single arguments, multiple arguments, and the distinction between validity and inductive strength. In the second part of the text, the basic criteria for an effective world view are discussed. These include: clarity and various pitfalls of language; definition; relevance; consistency (including truth tables and Venn diagrams); observation, memory and testimony; generalization and instantiation; analogical reasoning; causal reasoning; and explanation. The third part of the book includes applications, such as the nature of decision making, sales trickery, and political trickery. The book has numerous exercises. All even -numbered exercises are answered in the back of the text. The text also has an extensive glossary.