  We study the absorption and dispersion properties of a ${\bf \Lambda}$-type
atom which decays spontaneously near the edge of a photonic band gap (PBG).
Using an isotropic PBG model, we show that the atom can become transparent to a
probe laser field, even when other dissipative channels are present. This
transparency originates from the square root singularity of the density of
modes of the PBG material at threshold.
