Reliable data transport is an important facet of dependability and quality of service in wireless sensor networks. This paper gives an introduction to the reliable data transport problem and surveys protocols and approaches for this protocol, often developed for particular applications to reflect the applicationspecific dependability requirements. A joint characteristic of many of the discussed protocols is that they combine mechanisms from several layers to achieve their reliability goals while being energy-efficient. This very need to be energy-efficient precludes Internet-style approaches to reliability – handle it in the end system – and necessitates in-network solutions.