This issue of MMM is devoted to the proceedings of a 2-day Workshop which took place in Lecce (Italy) on 23-24 February 1995. It was dedicated to the memory of Professor Carmelo De Blasi, a well reknown scientist in the field of electron microscopy and a dedicated teacher, who died prematurely three years ago. To this event participated many researchers both from Italy and from abroad, who cooperated with De Blasi or had with him fruitful scientific discussions.