Chandra and XMM (and now Swift and Integral)  data have 
revolutionized our understanding of the number, luminosity and 
evolution of active galaxies from 0<z<4.  These results have
shown that the number of AGN,the evolution of AGN,the nature
of the hosts of AGN and the total energy radiated by AGN.
Were all incorrectly estimated by pre -2003 optical and radio 
surveys.  Since all theories on the origin, evolution and
nature of AGN were based on optical surveys a massive 
re-think is necessary.  I will discuss these results and add
some new results based on Swift hard x-ray data.