Progress in treating human acute renal failure (ARF) is dependent on developing techniques that allow for the rapid diagnosis, quantification of injury, further understanding of the pathophysiology, and the effects of therapy. Therefore, four techniques that will facilitate this progress are described and illustrated by four different investigative teams. Techniques to measure rapid changes in GFR are available for rapid diagnosis and quantification of ARF in humans. State-of-the-art magnetic resonance imaging (MRI) presently allows for enhanced resolution of regional renal blood flow and functional evaluations in patients. Furthermore, new probes and techniques for MRI that allow for identification and quantitation of inflammation, applicable to human ARF, are being developed and tested in animal models. Finally, two-photon microscopy will allow for four-dimensional cellular and subcellular studies in animal models of ARF providing rapid insights into pathophysiology and the therapeutic effects of a variety of promising agents. Further development and utilization of these techniques, especially in concert with genetic, proteomic, and molecular approaches, will allow for needed insights into the pathophysiology and therapy in human ARF.