This is a study of the Royal Bank of Canada’s Monthly Letter, which was initially created in 1920 as a traditional economic newsletter and later evolved quite serendipitously into a publication marvel when, in 1943, it came under the influence of John Heron, journalist and publicist, gaining mass appeal both domestically and abroad. This concise history documents the inception, development and rise to popularity of the Monthly Letter, telling the untold story of how a corporate newsletter became a tool of international public diplomacy. The purpose of this writing is to demonstrate the entanglement of the fields of public diplomacy and public relations and to offer a more palatable conceptualization of them as two discrete, but necessary, parts of a whole. It acknowledges the varied soup of contested terminology which surrounds the field of public diplomacy (e.g. corporate diplomacy, cultural diplomacy and economic diplomacy). This work conceptualizes public diplomacy and public relations as two parts of a whole in which the sum is greater than its individual parts, juxtaposing the two fields in relation to one another, diminishing neither. The contents of this work provide a broad overview of the fields of public diplomacy and public relations that could serve as an introduction and discussion point for students and scholars in both fields and offers a specific case study around which lively discussion and additional study can ensue.