Professor Lester Packer was, indeed, one of the great pioneers in the field of Free Radicals and Antioxidants. He founded the Oxygen Club of California (OCC), served as President for many years, and was President of Society for Free Radical Research International (SFRR-I). He also organized numerous international meetings all over the world always exhibiting exceptional interpersonal skills, and greatly promoting the scientific career of many young investigators. I had the great opportunity to personally enjoy his enthusiasm for excellence in science in many OCC meetings, and particularly I had the honor of organizing together with Josiane Cillard, João Laranjinha, and Enrique Cadenas the OCC World Congress in Valencia in 2015, in his last visit to Europe. Professor Lester Packer will forever remain a reference for all of us, and we are indebted to him for pursuing the investigation in this exciting area of redox signaling and antioxidants.