the not too distant future, wireless sensor networks are envisioned to proliferate through the entire spectrum of the environmental monitoring market allowing users to monitor a multitude of environments. Thousands or even millions of sensor nodes may span vast geographical areas enabling various environmental parameters to be monitored with significantly higher spatial and temporal resolutions than what is achievable using existing monitoring technologies. In order to manage the large amount of data that will be generated by these numerous sensor nodes, novel querying methods are needed to extract the required information in an energy-efficient manner. This paper studies the techniques used to manage the queries in a distributed manner and classifies the current state-of-the-art in this field into four main categories: in-network processing, acquisitional query processing, cross-layer optimization and data-centric data/query dissemination. This taxonomy not only illustrates how query management techniques have advanced over the recent past, but also allows researchers to identify the relevant features when designing sensor networks for different applications.