Project Summary/Abstract In the 21st century, advances in knowledge, research technologies, and analytical tools have created unprecedented opportunities for major breakthroughs in our understanding of fundamental biological principles and their underlying mechanisms. We propose here a new interdisciplinary program in Molecular, Cellular, and Developmental Mechanisms (MCDM) at Harvard Medical School (HMS) that will build on our recent investments in science infrastructure, education, and training. Our goal is to educate a diverse, rigorous, and independent group of scientists who will identify novel essential questions in mechanistic biology and develop incisive tools for addressing them. Based on our successful predecessor T32 program, we plan to recruit a group of 20 trainees per year beginning in their second year of graduate study from the Biological and Biomedical Sciences umbrella program. These 20 trainees will distribute across a group of 80 MCDM preceptor laboratories. Our approach to cultivating a resilient and creative group of scholars will be both evidence-based and student-centered. We will bring innovative programming to an exceptionally talented pool of trainees. Through continuous improvements in mentorship practice, community engagement and inclusion, we will foster a collaborative community of scholars who are well-prepared to make confident and transformative contributions to life science research and the many research-related careers needed to convert new discoveries about fundamental biological mechanisms into biomedical and life-sciences applications.