In this paper, we present calculational results and analysis for the effects of coherent pump dynamics, propagation, transverse and diffraction effects on SF emission from an optically-pumped three-level system. The full nonlinear, co-propagational aspects of the injuect pump pulse, together with the SF which evolves are explicitly treated in the calculation. Not only do our results relate strongly to previous calculations and experimental results in SF, but we introduce and demonstrate a new concept in nonlinear light-matter interactions, which we call light control by light. We show how characteristics of the Sf can be controlled by specifying certain characteristics of the injection pulse. This leads to possible applications in laser pulse control and shaping, nonlinear optical information encoding, and unique pulsed LADAR and millimeter wavelength sources.