Based on the detection of individually fluorescing molecules, localization microscopy (LM) is currently an established imaging modality in studies of cellular biology. Applied to live cells, LM provides the means to probe environments with single molecule precision and, moreover, provide information on elementary biological processes. High-speed LM involves generating discrete high-resolution snapshots of molecular distributions in living cells and single-particle tracking involves following the motion of individual molecules over time. This article details these two popular configurations of LM.