This booklet describes the basic curriculum design and staff organization of Project LEM, an experimental open education program at Hillers Elementary School in Hackensack, New Jersey. The LEM open education plan is characterized by differentiated staffing, multiage and multiethnic groupings, personalized instruction, a structured schedule, a core curriculum, and flexible use of space. Each LEM unit contains 100-150 children grouped on a multiage (two-year range) basis and operates with a staff of one team leader, one teacher per 26 students, and one aide. This is the same teacher-pupil ratio as for traditional classes in the school. In addition to basic skills instruction, each team teacher selects one area in either social studies, science, or cultural art to pursue in depth. Each child is assigned to a "home base" for a brief daily orientation and to specific groups for reading, language arts, and mathematics instruction on the basis of his or her skills achievement level. (Author/JG)