The Laboratory for Discrete Event Systems explores the theory and application of such formal methods as Petri nets and automata to model, analyze, control, evaluate and simulate complex engineering systems. By combining them with mathematical optimization theory, the Internet of Things, big data analytics, artificial intelligence, machine learning and intelligent optimization methods, the lab offers many powerful methodologies and tools to advance a wide range of systems and processes. They include wafer fabrication, flexible manufacturing, intelligent transportation, oil refinery, water processing, steel production, electronics manufacturing, high-speed rail transportation, disassembly, and de manufacturing. Over the past three decades, the lab has produced more than 900 papers, including more than 500 IEEE Transactions journal papers, 28 patents, 29 book chapters and 12 books. They have been used by industrial firms, leading to significant economic and societal impact.