For more than 30 years Prof. Luc Thévenaz has consistently made significant and fundamental contributions to fiber-optic sensing, as well as to the research and implementations of slow and fast light in optical fibres. He has addressed all aspects of the field from basic fundamental considerations through sophisticated pioneering implementations. He also launched in the mid-1990’s a pioneering activity in gas traces sensing based on spectroscopic techniques using near-IR and mid-IR semiconductor lasers. He has realized extremely sensitive systems based on a photoacoustic detection principle.