This paper consists of 13 chapters that describe a study of the effects of training in conflict resolution and cooperative learning in an alternative high school in New York City. Three of the school's four campuses participated, with Campus A receiving conflict resolution training, Campus C receiving cooperative and Campus B receiving training in both. For 2 years, staff training occurred at all three campuses in the form of after-school workshops. The student training in cooperative learning involved five principles: (1) positive interdependence; (2) fact-to-face interactions; (3) individual accountability; (4) interpersonal and small group skills; and (5) processing (analysis of group functioning with the goal of improvement). The conflict resolution training taught active listening, "I" messages, reframing the issues in conflict, criticizing ideas and not people, differentiating between underlying needs versus positions, distinguishing between negotiable and non-negotiable conflict situations, developing "win-win" solutions, and destructive and constructive negotiation styles. Data were collected with questionnaires to 350 students before and after training, performance ratings of students, teacher behavior evaluations, and supplemental interviews. The results indicate positive effects on the students. As students improved in managing conflicts they experienced increased social support, improved relations, higher self-esteem, increases in personal control, and higher academic performance. Included are 107 tables, 14 figures, and references and appendixes at the end of each chapter. (JB)