Abstract
The measurement of the strong-interaction effects in pionic hydrogen gives access to fundamental properties of the pion-nucleon interaction. Methods developed within the framework of Heavy-Baryon Chiral Perturbation Theory allow calculations with an accuracy of a few per cent. which should be tested by experiment. Techniques advanced for recent experiments on the precision spectroscopy of X-rays from antiprotonic and pionic atoms will be used in a new series of measurements for pionic hydrogen. The aim is to achieve finally an accuracy of 0.2% for the hadronic shift ε 1s and most important of about 1% for the broadening Γ 1s . An essential part of the experimental program is an improved understanding of the atomic cascade. At first, the value of ε 1s has to be proven not to be influenced by molecular formation. Secondly, a more accurate determination of Γ 1s requires a detailed study of Coulomb deexcitation.