It should be clear by now that beating the diffraction limit is extremely difficult. Nevertheless, a lot of research in optics has been and still is directed towards realising this goal. Many attempts...It should be clear by now that beating the diffraction limit is extremely difficult. Nevertheless, a lot of research in optics has been and still is directed towards realising this goal. Many attempts have been made, some successful, others not so, but, whether successful or not, most were based on very ingenious ideas. To close this chapter on diffraction theory, we will give examples of attempts to achieve what is called super-resolution.