In quest of perfection in electron optics: a biographical sketch of Harald Rose on the occasion of his 80th birthday.

This brief biographical sketch of Harald Rose on occasion of his 80th birthday describes some of the key events in an extraordinarily successful scientific life. Many of the theoretical concepts developed by him over the last 50 years have been fundamental for electron optics. Indeed, some of them have changed the whole complexion of this field and are fundamental to modern electron microscopy, both in TEM and in STEM mode. With this dedicated issue of Ultramicroscopy, the members of the electron microscopy community would like to thank Harald Rose for dedicating his professional life to their field and thereby enriching the life of those active in it.