Writers in the field of postal history have incredibly diverse interests and approaches. As a result, the postal history symposia have been organized around themes. The three themes represented in papers here are mail and the Civil War (2012), the development of transoceanic air mail service (2014), and the influence of postal treaties on post office reforms (2016).The American Civil War affected mail in many ways, particularly in the Confederate States of America, which faced the challenge of quickly developing its own postal system as well as shortages of supplies, in-cluding paper. The mail itself can be used to tell the story of the conflict through the examination of patriotic and propaganda images on envelopes and through the study of shifts in mail routes and practices as the war progressed.The histories of aviation and of mail delivery are intertwined. Pressure to deliver mail faster and more efficiently helped to propel investment in aviation innovations. In turn, developments in flight opened new possibilities for carrying the mail. The development of transoceanic air mail from its very early days in the 1920s through the rise of military air mail services during World War II is examined.Throughout much of history, mail has been the primary means of communication both within and be-tween nations; thus, the regulations and agreements concerning what may be mailed, and for what cost, have had a profound effect on a population’s access to information. Postal reform, and particularly the creation of national postal systems, required that immediate needs as well as political and economic visions of the future be considered and addressed legally and structurally during state-building. Cases of the United States in the revolutionary era and Brazil in the nineteenth century are examined.