Looping refers to the increasingly common practice of keeping groups of students together for two or more years with the same teacher. This booklet, first in a series of "Themes in Education" provides information on the educational practice of looping and includes selected current references on the topic. The booklet outlines the history of this practice, delineates its operating principles, differentiates looping from multi-age placement, and describes the academic and social benefits of the practice. Using a question and answer format, the booklet also answers questions commonly asked by parents, students, teachers, and administrators about looping. The booklet concludes with a description of the responsibilities and mission of the Northeast and Islands Regional Educational Laboratory at Brown University. Contains 32 references. (KB)