New infrared spectroscopy of 22 high-luminosity high-redshift AGNs helps to test several suggestions regarding the mass, composition and size of the emission line regions in active galacic nuclei (AGN). A plot of the metalicity luminosity correlation over more than five orders of magnitude in luminosity shows that most narrow line Seyfert 1 galaxies fall outside of the general trend. However, when L/LEdd is plotted instead of luminosity, all sources follow the same trend suggesting this to be the primary driver of the correlation. Regarding the narrow emission lines in the most luminous sources, there is a dichotomy in the observed properties where 2/3 of the sources show very strong [O III] lines while the remaining 1/3 have no detectable NLR. On the basis of this I argue that earlier proposed relations of the type $R_{NLR}\propto L_{{\rm [O III]}}^{1/2}$ must break down for RNLR exceeding a few kpc. Thus, NLRs in high luminosity AGN may be very different from those observed in nearby sources. In particular, some high luminosity sources may be in a phase of violent star-formation that produce a large quantity of high density gas in their central kpc.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html