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When nanostructures made of metals such as gold and silver are illuminated with visible light, plasmonic modes can be excited that cause conduction electrons to oscillate. This motion creates a pattern of electric fields, extending both within and outside the structure, that can be tuned by changing the particle size and shape to efficiently couple light to electronic processes. Practical applications of this coupling include improved harvesting of light for photovoltaics (1) and enhanced sensitivity for sensors based on light-emitting messenger molecules (2). Although there is well-developed theoretical understanding of how photons interact with nanostructures that are much smaller than their wavelength, we have few methods for measuring electric fields nearby and within nanoscale structures during photonic excitation. On page 59 of this issue, Yurtsever et al. (3) report using time-resolved electron energy gain/loss spectroscopy in an electron microscope to obtain spatially resolved maps of electric fields that result when nanoscale metal objects are illuminated by incident photons.