We have calculated Fe II emission-line strengths for active galactic n
uclei broad-line regions using precise radiative transfer and Iron Pro
ject atomic data. We improve the treatment of all previously considere
d excitation mechanisms for the Fe II emission, continuum fluorescence
, collisional excitation, fluorescence by self-overlap among the iron
lines, and fluorescent excitation by Ly alpha. We demonstrate that Ly
alpha fluorescence is of fundamental importance in determining the str
ength of the Fe II emission. In addition to enhancing the ultraviolet
and optical Fe II flux, Ly alpha fluorescence also results in signific
ant near-infrared Fe II emission in the 8500-9500 Angstrom wavelength
range. New observations are suggested to probe this effect in strong F
P II-emitting quasars.