I have discussed how observations of BAL QSOs can be used to constrain models for the BAL region and have speculated on how these constraints can be utilized to fit the BAL region into the framework of existing emission line region models. Additional observational work needs to be done in the areas of understanding selection effects so that BAL QSO and non-BAL QSO properties can be accurately compared. Larger samples are needed. Comparison of properties should not be limited to emission line properties, but should also include optical variability, polarization, continuum, x-ray and radio properties. Results from such work will influence the geometric constraints on models. Work in the area of deriving accurate column densities and extracting emission line profiles also needs to be done so that abundances and the possible correlation between BAL/emission line profile type can be further investigated. Imaging work on the low redshift BAL QSOs is very important as it may eventually provide some clue about aspect angle effects or which types of host galaxies are likely to have BAL regions with the largest BAL region covering factors.
A considerable amount of theoretical work is also necessary. It is important to consider in more detail simple geometric and kinematic models for the BAL flow to see if they can explain the relevant observations. At the same time, it is important to resolve the uncertainties associated with the ionization mechanism and abundances. Only then can the emissivity of the BAL clouds be considered in detail and accurately incorporated into emission line region models. It is also very important to continue to study the details of cloud acceleration, confinement and possible deceleration. This will not only help pin down a detailed model, but will allow a more accurate assessment of the possible pollution of the intergalactic medium by remnant BAL region ejecta.
Finally, in the context of interpreting QSO narrow absorption line work, it is important to continue to explore the possibility that some fraction of the narrow absorption line systems are intrinsic. If this is not properly accounted for, data being used to interpret galaxy halos, galaxy disks and the intergalactic medium at large redshifts may be in error.
I would like to thank Frank Briggs, Paul Coleman, Craig Foltz, Carl Grillmair, Cyril Hazard, Paul Hewett, Allen Schiano, Art Wolfe and especially Ray Weymann for useful collaborations and/or discussions in this work. I would also like to thank Chris Blades, Kostas Routsis and Diane Turnshek for thoroughly reading the manuscript prior to publication.