Theodor Hänsch was born in Heidelberg, Germany, in 1941. After receiving his doctorate from the University of Heidelberg in 1969 he continued his studies of laser science at Stanford University in Palo Alto, California. For his contributions to the development of laser-based precision spectroscopy, in particular measurements of atomic structures and optical frequencies with high accuracy, Hänsch was awarded the Nobel Prize in Physics in 2005. The “optical frequency comb technique” can be used to put fundamental theories in Physics to the test, but also to fine-tune global positioning systems or large astronomical telescope arrays. Today, Professor Theodor Hänsch continues his research at the Max-Planck-Institute of Quantum Optics and the Ludwig Maximilians University in Munich.