Liquid Mirror Telescopes: A Review

I review the present status of liquid mirror telescopes. In a nutshell: LMTs do work and several have been built and used. Extensive interferometric tests of liquid mirrors (the largest one having a diameter of 2.5 meters) show diffraction limited performance. A large quantity of astronomical data have been taken at the NASA 3- m LMT and are currently being analyzed. Finally, I shall address the future of the technology as well as the issues of the field accessible to LMTs equipped with novel optical correctors.