Matter is made up of atoms and electrons. Although seeing atoms is now possible, for example with modern electron microscopes, tracking atomic movements requires ultrashort measurement periods in the femtosecond and attosecond range, as well. Such extremely fast “camera shutter speeds” can be reached through ultrashort electron pulses, which are shorter than the time scale of the motion. The shorter the pulse, the higher the resolution. Equally important for experiments, however, is a special shaping of the electron pulses in space and time, adjusted to the properties of the substance in question.