A summary in English and analysis of the circular letters of the vicar-general of the Congregation of the Mission, Marc-Antoine Poussou. He took office because of the troubles and eventual resignation of the superior general, Jean-Baptiste Nozo. His interest in navigating his way through the difficulties posed by that resignation are evident in these letters. The circular letters were published in French in vol. 2 of the Recueil des principales circulaires des supérieurs généraux de la Congregation de la Mission, Paris, 1879. The pagination of the original has been maintained where possible. Unpublished circulars follow the appropriate published circulars, with an added letter (e.g., #3a).