It would be very ungracious not to say a few words about this remarkable set of presentations, even though it would be cruel to the audience to try to review them at this late hour. I made sixteen pages of summary notes of the highlights. We have heard about enormous improvements in our knowledge of the behavior of complex molecules in space. May I remind you that the computations of chemical equilibrium presented by Professor Klemperer covered largely the diatomic molecules known many years ago. The radio astronomers, with incredible technical proficiency, have found many polyatomic molecules with molecular weights close to a hundred; in a solid particle that causes continuous absorption we must reach weights near 108.