Infrared galaxies
  To study large-scale structure in the Universe a full census of the contents are required. This is even more important when the processes of galaxy formation are being investigated. In the last year the population of distant galaxies that emit most of their energy in the infrared waveband have been studied in unprecedented detail. The intensity of background radiation at wavelengths between 3 mm and 10 microns has been determined to within a factor of about 2, and much of this background radiation has been resolved into individual galaxies. These galaxies are largely hidden from view in the optical waveband by absorption due to interstellar dust. By combining this new knowledge with the ever growing body of information gathered using optical telescopes, the process of galaxy formation is slowly being revealed. Great opportunities for studying the distant Universe are promised by advances in instrumentation in the millimeter (mm), submm and far-infrared wavebands over the next decade. 
Andrew W. Blain (Cambridge)