There are many questions to be asked about the pedagogical practice of questioning. Questions provide insight into what students at any age or grade level already know about a topic, which provides a beginning point for teaching. Questions reveal misconceptions and misunderstandings that must be addressed for teachers to move student thinking forward. In a classroom discussion or debate, questions can influence behaviors, attitudes, and appreciations. They can be used to curb talkative students or draw reserved students into the discussion, to move ideas from the abstract to the concrete, to acknowledge good points made previously, or to elicit a summary or provide closure. Questions challenge students' thinking, which leads them to insights and discoveries of their own. Most important, questions are a key tool in assessing student learning. When practiced artfully, questioning can play a central role in the development of students' intellectual abilities; questions can guide thinking as well as test for it. Although many teachers carefully plan test questions used as final assessments of students' degree of experience with the course material, much less time is invested in oral questions that are interwoven in their teaching. Analysis of the kinds of questions they ask, whether they are oral or written, and the nature of the answers they elicit is even rarer. Given the important role of questions in teaching and learning, a method for collecting evidence about their own questioning strategies and a framework within which to analyze them has the potential to transform their teaching. Such a framework can be found in Bloom's (1956) Taxonomy of the Cognitive Domain, a classification system for cognitive abilities and educational objectives developed by educational psychologist Benjamin Bloom and his four colleagues (M. Englehart, E. Furst, W. Hill, and D. Krathwohl). Since its inception, Bloom's Taxonomy has influenced curriculum development, the construction of test questions, and their understanding of learning outcomes. It has helped educators to match the questions they ask with the type of thinking skills they are trying to develop, and to otherwise formulate or clarify their instructional objectives. Bloom's Taxonomy is based on the premise that there are distinct thinking behaviors that educators engage in that are important in the process of learning. Bloom and colleagues grouped these behaviors into six categories that ascend in their level of complexity: from knowledge, comprehension, and application at the lower levels to analysis, synthesis, and evaluation at the higher levels. This scheme orders the six categories into a hierarchy such that cognition at each level encompasses, builds on, and is more difficult than that at the levels below it. In turn, these categories provide a framework for classifying questions that prompt students to engage in these different thinking behaviors, and thus a tool for reflecting on their own questioning strategies used in teaching. (Contains 1 table and Links to Web Sites on Bloom's Taxonomy.