  The intrinsic Lyman-alpha emission lines of normal galaxies before
reionization are much absorbed by the damping wing of the Gunn-Peterson trough,
rendering their direct detection nearly impossible, if their intrinsic line
widths are less than ~100km/s. High redshift luminous quasars prior to the
completion of cosmological reionization at z~6, on the other hand, are capable
of producing large HII regions around them (Stromgren spheres) to allow their
intrinsic Lyman-alpha emission lines to be transmitted without overwhelming
absorption (Cen & Haiman 2000). We suggest that targeted observations at the
Stromgren spheres of known luminous quasars at z >= 6 would be able to detect
Lyman-alpha emission lines of galaxies inside the Stromgren spheres largely
unattenuated. A tunable, very narrowband filter of \Delta\lambda\over \lambda ~
0.1% or a narrowband filter of \Delta\lambda\over \lambda ~1% with follow-up
spectroscopic identifications will be required. Such observations could
directly observe the sources of cosmological reionization including possibly
the Pop III galaxies at z=6-20 by JWST. Possible applications include
determinations of the ionization state of the intergalactic medium, the sizes
of the Stromgren spheres, the ages of the quasars, the luminosity function of
high redshift galaxies and its evolution, the spatial distribution of galaxies
and its evolution, the biased distribution of galaxies around quasars and the
anisotropy of quasar emission. Observations using Keck-class telescopes may
already be made to enable a differentiation between a fully neutral and a 10%
neutral intergalactic medium at z>6.
