Explore the impact of C++ modules on large-scale software development in this ACCU 2019 conference talk by John Lakos. Delve into how modules will revolutionize program architecture, code organization, and deployment strategies. Learn about stable migration techniques for transitioning large codebases to module-based systems while maintaining compatibility with traditional header files. Gain insights from Lakos, a renowned expert in large-scale C++ development and author of influential books on the subject, as he shares his expertise on improving compilation speeds, reducing preprocessor reliance, and enhancing overall software design through the use of C++ modules.