The paper studies the institutionalization of a new domain of expertise dedicated to the exploration of the unknown in two established French technological firms with strong organizations of experts. The research is built in a comparative qualitative longitudinal research partnership with Renault (global car manufacturer) and SNCF (national railway company). This research highlights 4 main results: firstly, experts of radical innovation management are experts at managing the unknown in industrial contexts and breakthrough innovation strategic issues, wielding tools, and methods for breakthrough exploration. Secondly, experts of the exploration of the unknown support the other experts to explore the unknown. In this way (third result) this domain emergence highlights a new kind of interaction between innovation and expertise that (last result) cements breakthrough exploration capability as a strategic field.