We propose to explore the reasons why the different approaches to estimating the flexural response of the lithosphere in the Basin and Range province yield different estimates and to develop models that reconcile the discrepancies. By combining several types of data that are sensitive to different aspects of lithospheric deformation, it should be possible to substantially improve understanding of lithospheric rheology. Instead of just finding the best elastic thickness to fit a particular class of data the goal is to understand the tectonic and rheological processes responsible for the apparent rigidity and to develop techniques that will permit those processes to be more easily recognized.