The I3 Berkeley Science Connections Program (I3BSC) will build bridges from the undergraduate to graduate levels for traditionally underrepresented (UR) students. I3BSC focuses on the mathematical and physical sciences (MPS) in an effort to open the door for students from diverse backgrounds to key fields of modern science, in which underrepresentation of both ethnic minorities and women of all ethnicities is long-standing and remains severe. New bridges to and into the beginning years of graduate training will be built on research experiences of increasing intensity for undergraduates and incoming graduate students. The research activities will be fortified with systematic access to structured academic enrichment and professional development opportunities and resources, as well as a network of peers, near peers and scientists who are further advanced on the academic pathway and will serve as mentors. I3BSC targets the transition into graduate school for undergraduates in their junior and senior years and through the first two years of doctoral study. It focuses on the advancement of students into MPS careers, particularly academic careers, incorporating and also going beyond the goals of retention in science majors and completion of degrees. I3BSC?s approaches lend themselves to study and evaluation. We will examine if and how the variety and frequency of interventions effects UR advancement in science and the influence of particular interventions. For example, the mentoring aspect of the project will provide a unique window into learning how mentoring affects not only the mentee, but also the mentor. While there is a growing set of literature around instructional beliefs and practices within the classroom there is little published about this more informal aspect of academic life. Broader Impacts I3BSC is designed to take the highly effective work of four separate NSF programs that now work independently from each other at Berkeley, each operating with different MPS disciplinary foci and targeting different points on the educational pathway. I3BSC extends each of the four approaches to make them more uniformly and consistently available for all UR students at UC Berkeley who are majoring in any of the MPS departments at Berkeley or are entering any of our MPS doctoral programs. I3BSC will create new synergies that extend the work of these four key NSF-supported programs: Berkeley?s NSF-California Alliance for Minority Participation Program (CAMP), which supports students across STEM fields in undergraduate research experiences, community building and professional development; Berkeley?s NSF-AGEP program, The Berkeley Edge, which increases URM doctoral degree production, and advances PhD students and post-doctoral fellows to professorial careers; a NSF-supported program for mentoring lower-division students in Physics, the Compass and Society for Women in the Physical Sciences joint mentoring program; The NSF-Explorations in Statistics Research Program, which is an intensive week-long program for undergraduates to explore cutting edge research in Statistics. We will include students from all groups that add diversity under the post-Proposition 209 definition (URMs, women, students with disabilities, first-generation to college), because these groups are severely underrepresented in the mathematical and physical sciences, with a primary focus and priority given to those Berkeley students who are eligible for participation in CAMP, Compass-SWPS-PURNA, and AGEP.