Positron Microscopy, particularly by means of a scanned positron microbeam, offers an universal route to control positrons before and, in principle, after the implantation into condensed matter. Besides spatial resolution also the measurements of defect concentrations and specific trapping rates are enabled. The current technique and some results will be reviewed. Instrumental requirements will be discussed for studies of various defect configurations as well as for the more advanced techniques of multi-positron pulses and of a release of positrons from surfaces and other traps.