One of our industry’s greatest mechanical engineers, Mario Loiacono, passed away last week. To all who knew him, Mario was recognized as a great and loyal friend, a bottomless source of insight and knowledge, a mentor, a collaborator, and a wonderful person. I first met Mario in 2000, when we were pulled together to design Harvard University’s Laboratory for Integrated Science and Engineering in collaboration with Rafael Moneo. Mario’s depth of experience in designing high performance laboratory space was paramount to the success of the building, and his ability to indentify other key team members, such as Abbie Gregg and John Cox, helped round out the multi-disciplinary team needed to execute a complex project. He was always a welcome and friendly face at Labs 21, and his recent focus on sustainable design has left a lasting impression on me. His talk and unfinished book, “Diet, Nutrition and Exercise” used these terms as metaphors for sustainable design practices and drove home the importance and simplicity of sustainable concepts. I will miss him deeply.