This ERIC digest examines recent research about the use of manipulatives to teach mathematics. "Manipulatives" refers to objects that can be touched and moved by students to introduce or reinforce a mathematical concept. The digest also speculates on some of the challenges affecting future use of manipulatives. Since the 19th century, educators have advocated the active involvement of children in learning. Research suggests that manipulatives are particularly useful in helping children move from the concrete to the abstract level. Building the bridge between these levels, however, requires careful structuring of manipulatives by the teacher. Studies indicate that manipulatives can be effective when used properly. Issues relating to the implementation and success of manipulatives include the availability of manipulatives, the period of students' exposure to manipulatives, and teachers' experience and training. Two influences will probably affect the use of manipulatives in the future: schools' efforts to conform to the "Curriculum and Evaluation Standards for School Mathematics" and the commitment of state resources to transform theory into practice. Some state and local initiatives have mandated the implementation of manipulatives through policy, law, or curriculum documents. Among the states that mandate or encourage manipulative use are California, North Carolina, Tennessee, and Texas. The document concludes that further research is needed to shed more light on the effectiveness of manipulatives in both elementary and secondary schools. The document includes 10 references. (TES)