  We provide a physical interpretation of the first and second order terms
occurring in Ruelle's response formalism. We show that entropy fluxes play a
major role in determining the response of the system to perturbations. Along
this line, we show that our framework allows one to recover a wealth of
previous results of response theory in both deterministic and stochastic
contexts. In particular, we are able to shed light on the crosslinks between
the dynamical systems approach \'{a} la Ruelle and large deviations methods.
