I have a few questions about matter beams. 1. Is a matter beam simply a stream of particles? Can I make an alpha, electron or neutron beam by simply encasing a radioactive source in lead, punch out a hole and filtering out the rest? Can air rushing out of a tire in a vacuum chamber be considered as superposed nitrogen and O2 beams in the same sense as particle beams? 2. How would an electron beam from a such a source be different than that of a cathode ray? Is it only a difference in energy and momentum? 3. Is it possible to easily tune the "linewidth" (delta E of the many particles) of a matter beam? It this useful? 4. Can an actual or theoretical matter beam be coherent (like photons in a laser)? 5. Can we define a polarization to a matter beam? How is it related to its spin? (A circularly polarized photon has its spin oriented (anti-)parallel to its propagation vector. Are the spins of matter beam particles similarly oriented?) 6. Can we control neutron (or other neutral particle) beams with devices acting as mirrors, lenses, filters, scatterers etc.? 7. Can we make a superfluid He beam? 8. Can we make beams of exotic particles? (other than ions, e, protons, neutrons, photons, and alpha particles)?