2 v. : 24 cm, "A cooperative project [of] Social Studies Curriculum Center, Carnegie-Mellon University [and] Western Pennsylvania Conservancy.", TITLE ANALYTICS, Books accompanied by Teacher's manual [tch.man.], Preliminary edition of parts of book 1 published under the title World environmental concerns : a social studies unit by Robert Sweeney and preliminary edition of parts of book 2 published under title Environment and change : a social studies unit by George Gregory, Includes bibliographical references and index, [bk. 1] The world / Robert E. Sweeney -- [bk. 2] The nation / George Peter Gregory