Electromagnetic radiation in the extreme UV and soft x-ray spectral range is of steadily increasing importance in fundamental research and industrial applications. An optimum use of the available photons can only be achieved under condition of a comprehensive beam characterization. Following that goal, this work addresses the pathway of extreme UV and soft x-ray radiation from its generation, through the beam transport by the beamline to the probe position. Experimentally, those aspects are optimized at a laser-produced plasma source and at an arrangement for the generation of high-harmonics. Additionally, the coherence of laser beams is analyzed by measurements of the Wigner distribution function. This method is applied to the photon beam of the free-electron laser FLASH, resulting in the entire characterization of its propagation properties.weiterlesen