A study examined two projects designed to foster increased collaboration between secondary vocational and academic teachers. The first, called the Basic Skills Project, aimed at facilitating more effective cooperation among Idaho secondary school academic and vocational teachers to reinforce student mastery of basic skills. A part-time state project director worked with five teams of high school vocational and academic educators, providing in-service training and technical assistance in developing mechanisms to increase collaboration. The second project studied was an extensive curriculum revision project at Benson Polytechnic High School in Portland, Oregon. Semistructured interviews with key staff and other teachers, observations, analyses of project documents, and a levels-of-concern instrument were used to study the two projects. In the second year of the Idaho project, the staff from the five pilot sites served as resource people for five new sites, thus continuing to build on the collaboration that had developed at the original project sites. The Oregon curriculum revision project was similarly well received and generally successful. The study resulted in a framework for teacher cooperation, according to which teacher cooperation is necessitated by environmental influences, is enhanced by state-level and local administrative support, and results in tangible benefits to teachers and students. (This report also identifies barriers to and principles enhancing cooperation and illustrative practices.) An 11-item reference list and an annotated bibliography are also included. (MN)