Title: Putting Theory to Practice in Wireless Sensor Networks Someone once quipped "In theory, theory and practice are the same. But in practice they're different." I will argue that in the area of wireless sensor networks, given their resource constraints and diverse challenges, it is crucial to bridge the gap between the two. I will describe results from some ongoing studies that span the wide spectrum between deep theory and experimental research. These include: a fundamental theoretical result showing that all monotone properties in geometric random graphs exhibit sharp phase transition thresholds; analytical explanations of empirical observations on wireless link characteristics; an analysis of the impact of spatial correlations on joint routing and compression showing the existence of near optimal clusters; design and analysis of the ACQUIRE active querying technique; techniques for delay efficient scheduling; and the design of Ecolocation --- a novel sequence decoding algorithm for RF-only localization.