The book shows how productive historical, social and economic research questions to philatelic and postal history sources can be and makes civic knowledge accessible for university research as well. The 19th century saw changes in the postal system: The development of a transport infrastructure with the help of railroads; the emergence of nation states and newly tailored areas of responsibility in the postal system, as well as the founding of the Universal Postal Union; the invention of the postage stamp and thus a visual means of communication in miniature. But the 20th century also offered upheavals for the postal system: World War I and World War II as well as disintegrating colonial empires resulted in a new world order, which can be seen both in changing postal administrations and on the motifs of postage stamps. At the end of the 20th century, privatization of the postal system took place in many countries, calling into question the function of postal stamps as an expression of state symbolism. The contributions show how interwoven transport infrastructure, postal system, state organization, and stamp motifs are and how they are mutually dependent on each other.