A selection of results from electron-positron collisions at BESIII are reviewed. The results presented here illustrate the wide range of physics topics that can be studied using the Beijing Electron Positron Collider (BEPC). At low collision energies, the cross section for e+e- to pi+pi- provides much-needed input into theoretical calculations of the anomalous magnetic moment of the muon, and the reaction e+e- to proton-antiproton provides access to the electromagnetic form factors of the proton. In the charmonium region, a large sample of psi' decays can be used to measure new decay modes of charmonium states. And at higher energies, BESIII is uniquely situated to explore questions concerning the still-unexplained XYZ states.