This paper proceed with a revision of the basic principles involved in a method of optical microtopography that we are developing, presenting recent improvements. It is shown that a collimated light beam with a oblique incidence on a surface can be used to assess its distance from a reference plane if the bright spot produced on the surface is imaged onto a array of detectors which tracks its lateral displacement. The light beam is swept over the surface, so that large areas can be scanned. An account is given of some practical applications of the system. The system has been used with success to measure surface roughness of machined surfaces, thickness measure of silver and copper thin films, for the topographic inspection of the edge of silver films sputtered through different masks, for the surface inspection of polyethylene films and for non contact measurement of fabric thickness and relief mapping.