In 2013, the National Board for Professional Teaching Standards received a 5-year Investing in Innovation Fund Development grant from the U.S. Department of Education to develop, implement, and study Accomplished Teaching, Learning, and Schools (ATLAS). ATLAS is an online case library that contains examples of "accomplished teaching" practice delivered by National Board Certified Teachers. A purpose of the grant activities was to expose preservice and early career teachers to ATLAS content, which was hypothesized to affect their teaching practice and the achievements of their students. This final report summarizes research on the first 2 years of the program's implementation at scale (during the grant's fourth and fifth years), and the effects of ATLAS use on the outcomes of preservice and early career teachers and on the mathematics and science achievements of students in Grades 3-6. The study team determined that ATLAS was implemented with fidelity at the institution of higher education and local education agency levels during the second study year but not the first study year. Regarding the effects of ATLAS use on the outcomes of preservice teachers, early career teachers, and students, the study did not identify any observable differences between ATLAS users and non-ATLAS users or their students. [This report was funded by the National Board for Professional Teaching Standards (NBPTS) through a U.S. Department of Education Investing in Innovation Fund grant to NBPTS.]