In this formative study of the Babylonian and Assyrian letters, originally published over three articles in Beiträge zur Assyriologie, Delitzsch presents in transliteration and translation, 40 Akkadian letters, along with critical notes and remarks. These letters are addressed to the Queen-Mother and to the King and generally date from the Neo-Assyrian and Neo-Babylonian periods and contexts. An example of early analysis of the still-young discipline of Assyriology, this study provides insights into the dynamics of royal life in the late Mesopotamian empires.