Host galaxies and environment of BL Lac objects
  Since the last meeting on BL Lac objects 10 years ago, BL Lac host galaxies and their cluster environment have gained much attention. Hence, our current knowledge of the properties of BL Lac host galaxies and their cluster environment has improved considerably, which will be reviewed. The importance of future observing programs using (very) large telescopes is briefly outlined. 
J. Heidt (Landessternwarte Heidelberg, Germany)