the lower optical depth of the PNe in the IR as compared to optical wavelengths allows us to potentially see into regions of the nebula that are obscured by dust.

There have been several previous surveys that have explored the properties of PNe in the infrared. Early spectroscopic and photometric surveys (e.g., Gillett, Merrill, & Stein 1972; Cohen & Barlow 1974) determined that there was an excess of IR emission over what was expected from reflected continuum emission from the central star. Other photometric surveys in the following years (Whitelock 1985; Persi et al. 1987) determined the primary sources of IR emission to be stellar continuum, thermal dust emission, and thermal & line emission from the nebula itself. The near-IR color characteristics of most PNe are unique and can be used to identify new PNe and post-AGB objects (Garcia-Lario et al. 1990).

Recently there have been more detailed spectral observations of PNe in the near-IR. Hrivnak, Kwok, & Geballe (1994) surveyed a set of proto-PNe in the H and K bands. In these objects the Brackett lines were observed in absorption, and most objects had CO absorption or emission, indicating recent mass loss events. Rudy et al. (1992, and references 