The scientific community of quantum science learned with deep sadness the death of Claude Cohen-Tannoudji on October 22. He pioneered the manipulation of atoms by light, and was awarded the Nobel prize in physics in 1997 for his work on laser cooling of atoms. His fundamental research, motivated by understanding physical phenomena, led to numerous developments in quantum technologies. He was also a remarkable teacher, and whole generations of physicists learned quantum mechanics through his books and attended his lectures at Collège de France, where he lectured for 40 years until 2003. All our thoughts go to his family and friends.