Nonlinear problems in classical and quantumelectrodynamics.- On the stability of solitons.- Spectral transform and nonlinear evolution equations.- Spectral transform and solvability of nonlinear evolution equations.- The spectral transform NS a tool for solving nonlinear discrete evolution equations.- Hyperbolic balance laws in continuum phyisics.- Mathematical aspects of classical nonlinear field equations.- Non-linear transport equations : Properties deduced through transformation groups.- Nonlinear kinetic equation in plasma physics leading to soliton structures.