In recent years laser light has been used to control the motion of electron waves. Electrons can now be diffracted by standing waves of light. Laser light in the vicinity of nanostructures is used to affect free electrons, for example, femto-second and atto-second laser-induced electrons are emitted from nanotips delivering coherent fast electron sources. Optical control of dispersion of the emitted electron waves, and optically controlled femto-second switches for ultrafast electron detection are proposed. The first steps towards electron accelerators and matter optics on-a-chip are now being taken. New research fields are driven by these new technologies. One example is the optical generation of electron pulses on-demand and quantum degen...