The National Science Foundation (NSF) awarded a $300,000 Project Grant under its Computer and Information Science and Engineering (CFDA 47.070) federal grant program to Carnegie Mellon University (CMU). The grant funds a 3-year research project focused on developing logical and semantic foundations for compositional assurance reasoning about the safety, reliability, and security of software systems when heterogeneous analysis methods are applied. The project aims to create reasoning principles that can formally compose results from different types of software analysis, such as testing, static analysis, and code review. Additionally, the research will investigate how counterfactual reasoning can aid the refinement of software analyses and program repair when incidents occur. This grant provides training opportunities for undergraduate and graduate students in areas including program testing, verification, vulnerability detection, and software security.