This book presents a coherent introduction to the fundamental concepts of argumentation and debate, argumentation theory, and critical thinking. As the title suggests, the reader learns how to use argumentation effectively as a means of discovering what is worthy of belief and for gaining the support of others. Now comprised of nineteen in-depth chapters, this best-selling book offers a broad view of argumentation. The first two sections explain the field invariant concepts of critical inquiry. These chapters feature such concepts as propositions, data, inductive and deductive forms of argument, and fallacies. The third section examines the application of argumentation in advocacy situations. Readers will learn about propositions of fact/value and policy, the implication of argument fields and the narrative paradigm on the development and evaluation of argument, and the unique rhetorical challenges involved in communication arguments. The final section offers description and in-depth consideration of affirmative and negative strategies. In addition, the discussion of refutation and cross-examination is comprehensive and useful to both academic debaters and non-debaters.