Coupled theoretical and computational work is presented aimed at understanding and modelling stimulated Raman backscattering (SRBS) relevant to laser–plasma interactions in large-scale, homogeneous plasmas. With the aid of a new code for simulating and studying the nonlinear coupling in space–time of a large number of modes, and an Eulerian Vlasov–Maxwell code for studying the evolution of large amplitude electron plasma waves, we report results and their interpretations to elucidate the following five observed, nonlinear phenomena associated with SRBS: coupling of SRBS to Langmuir decay instabilities (LDIs); effect of ion-acoustic damping on SRBS; cascading of LDI; stimulated Raman scattering cascades; and stimulated electron acoustic wave scattering (SEAS).