Welcome to the largest teacher training organization in the United States and our Teacher Boutique. Training Institute (ATI) has helped over 1.5 million educators throughout the United States and Canada as well as other countries of the world reach their goals to make a positive difference in the lives of the children in their classrooms Our trainings are comprehensive, inspiring, and packed with research and evidence-based strategies. Since Maryln Appelbaum and Marty Appelbaum gave their first seminar in 1989, ATI has grown into an institute with many team members and industry leaders.