This document discusses critical thinking, what it is, why it is important, and how it improves teaching and learning. It defines critical thinking as a self-directed process of taking deliberate steps to think at the highest level of quality. It distinguishes between "green thinking," which is instinctive and spontaneous, and "red thinking," which analyzes, assesses, and improves green thinking. Critical thinking leads to substantive learning by applying intellectual standards to thinking and eliminating biases and dysfunctional thought patterns. The document encourages readers to analyze problems in their own thinking and identify areas for improvement.