Short answers, pulled from the story.
The Memorial of Saint Helena was written by Emmanuel de Las Cases, a companion who accompanied Napoleon Bonaparte into exile on Saint Helena beginning in 1815. Las Cases transcribed near-daily conversations with the former Emperor, with his son Emmanuel producing fair copies of the notes.
The Memorial of Saint Helena was first published in 1823, after Napoleon's death. It was reprinted within less than a year of publication and translated into English, German, Italian, Spanish, and Swedish.
Las Cases was arrested on the 25th of November 1816 after being found in possession of personal letters he was trying to send secretly to Europe. He was expelled from Saint Helena a month later by order of the island's governor, Hudson Lowe, and the manuscript of the Memorial was confiscated by British authorities.
The Memorial entered popular imagination as Napoleon's own personal and political testament, which made it a founding text in the development of the Napoleon cult and the ideology of Bonapartism. Readers treated it as the former Emperor's direct voice rather than as a journalist's record.
The original manuscript is held in the British Library, deposited there in 1965 by the family of Lord Bathurst, whose ancestor Henry Bathurst, Secretary of State for War and the Colonies, had received the confiscated manuscript from British authorities in 1816.
Charles de Gaulle used The Memorial of Saint Helena as inspiration for his own memoirs. De Gaulle led Free France during World War Two and served as President of France from 1958 to 1969.