Neutrino experiments over the past ten years have conclusively observed neutrino flavour oscillations, indicating that neutrinos have non-zero masses. I will briefly describe the physics of neutrino oscillations, focusing on the experimental evidence from solar, reactor, atmospheric and accelerator neutrinos. I will then describe MiniBooNE, an experiment at Fermilab designed to confirm or rule out the LSND signal, which is the only oscillation observation that has yet to be independently confirmed. Taken together with the other oscillation results, the LSND signal is not compatible with the Standard Model prediction of three neutrino flavours. MiniBooNE performed a "blind" analysis, where all analysis selections and fitting procedures were determined before candidate oscillation neutrino events were examined. First oscillation results will be presented.