Peter Neumann, longtime SRI International researcher and founder of the RISKS Digest, died May 17 2026 in Santa Clara from complications following a fall. The announcement appeared first on the Multics and TUHS mailing lists citing family and colleague Robert Watson. https://www.csl.sri.com/~neumann/ Neumann's four-decade record at SRI included principal contributions to the Multics security kernel, the Provably Secure Operating System project, and decades of formal-methods guidance for critical infrastructure. Primary records from the Multics list and Neumann's own SRI archive document his role in shaping the 1970s-1990s trusted-systems criteria later adopted by NSA and NIST. Subsequent coverage has under-emphasized his direct influence on the Common Criteria and on the design of separation kernels still used in avionics and voting systems. Mailing-list archives show Neumann maintained active correspondence on these topics into 2025, linking early Multics access-control work to contemporary verified microkernels such as seL4.