Abstract | Understanding the implementation of a certain feature of a system requires to identify the computational units of the system that contribute to this feature. In many cases, the mapping of features to the source code is poorly documented. In this paper, we present a semi-automatic technique that reconstructs the mapping for features that are triggered by the user and exhibit an observable behavior. The mapping is in general not injective; that is, a computational unit may contribute to several features. Our technique allows to distinguish between general and specic computational units with respect to a given set of features. For a set of features, it also identies jointly and distinctly required computational units. The presented technique combines dynamic and static analyses to rapidly focus on the system's parts that relate to a specic set of features. Dynamic information is gathered based on a set of scenarios invoking the features. Rather than assuming a one-to-one correspondence between features and scenarios as in earlier work, we can now handle scenarios that invoke many features. Furthermore, we show how our method allows incremental exploration of features while preserving the \mental map " the analyst has gained through the analysis.