Preparing students to make contributions in the fields of science, statistics, mathematics, and technology is critical for our country to remain a world leader. To accomplish this, it is important for our middle and high school mathematics teachers to be well prepared for teaching mathematics. The Mathematics of Doing, Understanding, Learning and Educating for Secondary Schools (MODULE(S2)) project will create course materials that will be used to develop preservice teachers' mathematical knowledge as it relates specifically to the work of teaching geometry, statistics, algebra, and modeling. These modules will be used in university mathematics courses and piloted with faculty at universities and colleges of all types across the United States. The project will promote effective instruction by offering professional development activities for faculty using the modules during the summers and the school year. Additionally, the project will investigate the impact of instruction with the modules on preservice teachers' knowledge and inform nationwide efforts in teacher education. This five year project will build on efforts by the Mathematics Teacher Education Partnership (MTE-P) to create a gold standard for the preparation of secondary mathematics teachers across its 90 member universities. Evidence has mounted in recent decades that to implement sound mathematics instruction, teachers must possess understandings of content that are specifically applied in the work of teaching (mathematical knowledge for teaching - MKT). To develop MKT, preservice teachers need opportunities to use mathematical knowledge to recognize, respond to, and understand mathematical issues that arise in the context of teaching. Findings from small pilots with initial geometry and statistics modules developed by the project indicate an increase in preservice secondary teachers' MKT. MODULE(S2) will expand these materials and examine the conditions of instruction that impact preservice teachers' MKT, development of MKT, and expectancy and value in using MKT as a resource for teaching. The project will use mixed methods to provide empirically-based accounts of how factors of quality of instruction and of instructional resources impact preservice teachers' MKT. In addition, results will be used multiple times per year to improve the MODULE(S2) materials through improvement cycles carried out as a part of the Networked Improvement Community design. The Robert Noyce Teacher Scholarship program is providing co-funding for this project in recognition of its alignment with the broader teacher preparation goals of the Noyce effort.