What do we want, what do we have, what can we do? (unfolding in LHC era)

Nonparametric estimation of measured distribution is essential before extracting the parameters even if a model exists. We consider the model of measurements in the general form Ks=s′. High-precision measurements in the LHC era require that errors should be allowed for in both the operator K and the right-hand side s′. Several algorithms to solve the problem are discussed and the existing software is reviewed.