Description
In this talk, I will give an overview of the status of our theoretical understanding of the muon anomalous magnetic moment. I will then focus on the contribution of the hadronic vacuum polarization, for which significant discrepancies between "data-driven" estimates based on cross-section data for $e^+e^-$ to hadrons and lattice computations are emerging. In the latter part, I will concentrate on the discrepancy between data-driven and lattice-based values for the light-quark connected part of the so-called RBC/UKQCD window quantity, which constitutes a part of the hadronic vacuum polarization for which very precise estimates are available.