  We examine fully coherent two-pulse propagation in a lambda-type medium,
under two-photon resonance conditions and including inhomogeneous broadening.
We examine both the effects of short pulse preparation and the effects of
medium preparation. We contrast cases in which the two pulses have matched
envelopes or not, and contrast cases in which ground state coherence is present
or not. We find that an extended interpretation of the Area Theorem for
single-pulse self-induced transparency (SIT) is able to unify two-pulse
propagation scenarios, including some aspects of electromagnetically-induced
transparency (EIT) and stimulated Raman scattering (SRS). We present numerical
solutions of both three-level and adiabatically reduced two-level density
matrix equations and Maxwell's equations, and show that many features of the
solutions are quickly interpreted with the aid of analytic solutions that we
also provide for restricted cases of pulse shapes and preparation of the
medium. In the limit of large one-photon detuning, we show that the two-level
equations commonly used are not reliable for pulse Areas in the 2$\pi$ range,
which allows puzzling features of previous numerical work to be understood.

Quantum Physics;Pattern Formation and Solitons