Theoretical Characterization of the Trends in Halogen Bonding -- The Interaction of Dihalogens and Hydrogen Halides with Lewis Bases in the Gas Phase: An Experimental Comparison of the Halogen Bond and the Hydrogen Bond -- Halogen Bonding with Dihalogens and Interhalogens -- Halogen Bonding in Crystal Engineering -- X-ray Structures and Electronic Spectra of the ?-Halogen Complexes between Halogen Donors and Acceptors with ?-Receptors -- Halogen-bonded Liquid Crystals -- Halogen Bonding in Conducting or Magnetic Molecular Materials.