This update of the "Learning by Design" Sourcebook expands the previous compilation of resource information and materials on environmental education projects, curriculum materials, books, people, and organizations. It, like the original sourcebook, is divided into four sections: (1) models--presenting basic features, descriptions, and historical development of and sample activities from exemplary environmental education programs; (2) resources--containing descriptions, representative illustrations, and sample activities from commercially available publications; (3) bibliography--containing annotated entries on various topics; and (4) networks--presenting lists of people/organizations involved in environmental education. Additions to the models, resources, and bibliography sections, and a completely new network section are provided, together with instructions on how to incorporate them into the existing sourcebook. Four additional models, 10 additional resources (and a new index for this section, reflecting the addition of these items), additional bibliography pages, and a completely new network section (replacing the current section) are included. Forms for making suggestions for future entries for each of the sections are also included. (JN)