Benjamin Bloom (1913 - 1999) was an educational theorist and a teacher who developed a 6-level classification for intellectual development .

The systems levels are knowledge, comprehension, application, analysis, synthesis, and evaluation. His theory, known as Bloom's Taxonomy, incorporates cognitive, psychomotor, and affective spheres of knowledge into the learning hierarchy. While working at the University of Chicago in the 1960s, he wrote two important books, Stability and Change in Human Characteristics and Taxonomy of Educational Objectives. His theories were adopted by many public school districts, particularly in Chicago and Boston, during the 1970s and 1980s, but have since then been widely criticized as being ineffective, and in many places they are no longer practiced. His theory can be summarized by the following quote by Bloom: "The purpose of education is to change the thoughts, feelings and actions of students."