Peter de Groot is fascinated by interference fringes and their practical use for measuring things. He began his optics career by building a reflecting telescope fifty years ago, grinding and polishing the main mirror by hand, and testing it with the Foucault knife-edge test. Educated first in History and the liberal arts, then in experimental Physics at the Universities of Grenoble, Maine, and Connecticut, he enjoys discovering the underlying principles and hidden links behind creative work in science and engineering. His research has led to 140 US patents for optical instruments, as well as over 220 technical papers, tutorials, and book chapters. He is a Fellow of SPIE, Optica, the Institute of Physics, and the International Academy of Engineering and Technology, and is a recipient of the Lifetime Achievement award from the American Society for Precision Engineering. An experienced teacher and lecturer, he is a short-course instructor and honorary professor. Dr. de Groot is also the 2025 President of SPIE, the International Society for Optics and Photonics.