Microscopic theories beyond mean-field are developed to include pairing, in-medium nucleon-nucleon collisions as well as effects of initial fluctuations of one-body observables on nuclear dynamics. These theories are applied to nuclear reactions. The role of pairing on nuclear break-up is discussed. By including the effect of zero point motion of collective variables through a stochastic mean-field theory, not only average evolution of one-body observables are properly described but also fluctuations. Diffusion coefficients in fusion as well as mass distributions in transfer reactions are estimated.