PHOTOIONIZATION MODELING COMPRISES ANY SITUATION IN WHICH ENERGY IN THE FORM OF ELECTROMAGNETIC RADIATION IS THEN RE-PROCESSED BY GAS WHICH BECOMES IONIZED AND HEATED AND THE EXCESS ENERGY IS RE-EMITTED INTO LONGER WAVELENGTH SPECTRAL LINES AND DIFFUSE CONTINUUM. THUS FAR MODELING OF ASTRONOMICAL PHOTOIONIZED PLASMAS IS GENERALLY DONE FROM THE CONDITION OF STEADY-STATE STATISTICAL EQUILIBRIUM WHICH MEANS THAT GAS IONIZATION IS BALANCED BY RECOMBINATION ATOMIC EXCITATIONS ARE BALANCED BY SPONTANEOUS AND INDUCED DE-EXCITATIONS AND ELECTRON HEATING IS BALANCED BY COOLING. A NOTABLE EXAMPLE OF PHOTOIONIZED SPECTRA ARE THE WARM ABSORBERS ABSORPTION LINES AND EDGES IN THE X-RAY AND UV SPECTRA OF ACTIVE GALAXIES (AGN). THE FEATURES ARE BROADENED AND BLUESHIFTED RELATIVE TO THE OPTICALLY DETERMINED REDSHIFT INDICATING THAT THE GAS IS FLOWING OUTWARD RELATIVE TO THE FRAME OF THE GALAXY AT SPEEDS ~1000 KM/S. THESE FEATURES ARE FOUND IN A LARGE FRACTION (~ 50%) OF LOW LUMINOSITY AGNS. THERE ARE STRONG INDICATIONS THAT X-RAY WARM ABSORBERS AND AGN OUTFLOWS IN GENERAL MAYBE DOMINANT CONTRIBUTORS TO THE AGN FEEDBACK MECHANISM WHICH DETERMINE THE COEVOLUTION OF SUPERMASSIVE BLACK HOLES AND THEIR HOST GALAXIES. MOREOVER THERE IS INCREASING OBSERVATIONAL EVIDENCE THAT THE AGN HOSTS OF SOME X-RAY WARM ABSORBERS MAY BE AT THE TRANSITION BETWEEN MASSIVE STAR FORMATION AND QUIESCENT ELLIPTICAL STELLAR POPULATION.