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This review has given a brief summary of the properties of galaxies as viewed in the radio background. In conclusion, it is worth emphasizing three points:

  1. Although some factors such as galaxy mass and Hubble type strongly dispose a galaxy to host a radio-loud AGN, we still have no definite understanding of why this should be so. Other `distinguishing marks' of radio galaxies might be helpful in this process, but few if any are clearly established.

  2. With certain exceptions (such as the situation at z gtapprox 2), we have a good statistical description of how the abundance of radio AGN evolves. Again, though, we are very far from understanding why active nuclei found it so much easier to function at high redshift.

  3. High-redshift radio galaxies should probably not be thought of as in any way primeval. If we ignore the few dozen most luminous sources in the universe, then the optical/IR properties of high-redshift radio galaxies are consistent with those of radio-quiet ellipticals. They appear to be red and old: theories in which most massive galaxies complete their star formation at z gtapprox 4 are required.