Gunter Stein, a renowned pioneer in the field of control systems and theory, passed away at the age of 84. Over a distinguished career, Stein made monumental contributions to aerospace engineering and multivariable control, significantly shaping modern flight control systems. He held prominent academic and industry roles, including serving as a principal research fellow at Honeywell and lecturing at the Massachusetts Institute of Technology. Colleagues and students widely remembered him as a brilliant mentor whose rigorous theoretical insights bridged the gap between academic research and practical engineering applications. His enduring legacy continues to influence the safety and precision of modern aviation and automated control technologies worldwide.