We present a general framework for studying regularized estimators; such
estimators are pervasive in estimation problems wherein "plug-in" type
estimators are either ill-defined or ill-behaved. Within this framework, we
derive, under primitive conditions, consistency and a generalization of the
asymptotic linearity property. We also provide data-driven methods for choosing
tuning parameters that, under some conditions, achieve the aforementioned
properties. We illustrate the scope of our approach by presenting a wide range
of applications