The first Brief in the 4C's sub-series of the STREAM Series. Critical thinking is the basis for comprehending the world around us therefore it is essential for children to acquire this skill, starting in the classroom. This brief will teach how to apply the 4C's: critical thinking, creativity, communication, and collaboration. By breaking down broad ideas such as critical thinking, teachers will learn how to illustrate a better understanding of it by sharing real world problems, examining evidences that supports a solution, and questioning to evaluate or resolve. This book also discusses how Catholic critical thinking can engage the distinct view of reality based on Catholic anthropology or wordly views. This brief offers guidance on how to teach critical thinking though instructional strategies, assessment strategies, and tables which show how to further implement the 4C's.