(Submitted 14 February 1986) Zh. Eksp. Teor. Fiz. 92,46-55 (January 1987) The coherent resonant interaction between multifrequency light and a multilevel system is considered together with the N-wave interaction of wave packets in a medium with a quadratic nonlinearity. The Lax representation of the self-consistent set of Maxwell-Bloch equations for this interaction is found. Soliton solutions resulting from the parametric transformation of ultrashort pulses in three- and four-level system (N = 3, and N