A high-speed transmission electron microscope was developed for probing laser-induced fast nonperiodical processes on the nanosecond time scale. 7-11 ns illuminating electron pulses—up to three—are produced by a laser pulse-driven photocathode. The electron gun can be used both for nanosecond exposure and conventional stationary operation. The introduced microscope is operated in three different modes for investigations of laser treated thin films: (1) Bright-field imaging, tracking changes of the texture and transport of neutral material; (2) dark-field imaging, mapping transient plasmas; and (3) selected area diffraction to study fast phase transitions. Presently, the space resolution is ≈200 nm.