These proceedings provide an overview of the research carried out to date on B-type stars with forbidden emission lines and dusty envelopes. These objects may represent an important transition stage in the evolution of many early-type stars, but they have been little studied. The text brings together the information available on the distribution, absolute magnitude, spectra in all wavelength ranges, photometric properties and variability of these objects. Also discussed are the different theoretical models proposed for explaining the amazing variety of phenomena observed.