This chapter describes narrow-bandwidth filtering of soft X-rays by diffraction gratings in optical systems known as monochromators for the purpose of performing spectroscopic measurements. The X-ray sources considered are confined to broadband sources generated by synchrotron storage-ring facilities and beamlines at these facilities, which consist of monochromators and associated optics to collect the source radiation and focus it at the sample position. A brief history of soft X-ray synchrotron beamlines, from the 1970s to today, is provided, separated into three eras of beamline development that correspond to the three generations of synchrotron storage rings. The advantages and dis­advantages of the principal types of beamlines from the three eras is provided, along with a more detailed description of the latest generation of soft X-ray beamlines. The dramatic improvements in flux (greater) and spot size (smaller) over the 50-year history of synchrotron beamlines are described.