During the past 8 years excimer lasers have made an enormous progress both in power and energy. Today they are the most important high power laser source in the uv-spectal range. The paper will present the basic concept of excimer lasers including the spectoroscopy and the kinetic of the lasing process. Based on these data the most practical excitation mechanism, the fast discharge, will be discussed. Limitations and technical constraints of power density and efficiency will be given. The physical properties of the excimer laser radiation i.e. bandwidth, tunability, coherence and pulse duration have been of major concern in the last few years. Concepts will be discussed by which the difficulties connected with the high gain of the laser medium can be surpassed. Today the laser radiation can be controlled within 0.2 cm-1 bandwidth and within three to four times the diffraction limited divergence angle. Inadditiorycluring the past year, devices have been developed allowing pulses with durations of several ps and 30-40 mj energy. Parallel to these physical improvements the reliability of the excimer laser has reached such a high level that they are now introduced in industrial processes. The limitations of the most critical parts of excimer lasers will be presented together with the evaluation of running costs. Finally some selected examples of applications of this new work horse of uv radiation will be discussed.