  Propagation of ultrashort optical pulses in a dense resonant medium is
considered in the semiclassical limit. In our analysis, we place emphasis on
several main points. First, we study transformations of spectra in the process
of pulse propagation and interactions with another pulse. The second point
involves the transient processes (including pulse compression) connected with
self-induced transparency soliton formation inside the medium. Finally, the
third aspect is the study of collisions of co- and counter-propagating pulses
in the medium. In the last case, the investigation of symmetric and asymmetric
collisions shows the possibility of effectively controlling the parameters of
transmitted radiation.
