Issued by Deutsche Bundespost Berlin in 1974, this 40 Pfennig commemorative stamp honors Adolf Slaby (1849–1913), a pioneering German engineer and physicist. Slaby was instrumental in developing early wireless telegraphy in Germany and collaborated closely with Ferdinand Braun. The stamp design features a striking profile portrait of Slaby, with red concentric wave patterns symbolizing radio transmission — a tribute to his work in wireless communication. The vertical inscription “DEUTSCHE BUNDESPOST BERLIN” marks its issue for West Berlin.

Design Elements:

• Portrait: Adolf Slaby, in formal attire, with distinctive glasses and mustache.

• Background: Radiating wave lines symbolizing electromagnetic signals.

• Colors: Deep red and black on white paper.

• Denomination: 40 Pfennig.

• Issue Year: 1974.

Collector’s Notes:
This stamp forms part of Berlin’s series honoring German scientists and inventors, celebrating the centenary of Slaby’s birth. It is appreciated for its elegant engraving style and its thematic connection to radio technology and communication history.