At the time of their meeting at Odessa, Peierls spoke no Russian and Genia no German. Their shared language was English, which Peierls says 'Genia could speak reasonably but not fluently', and this continued to be the medium of their correspondence. Peierls however started taking Russian lessons 'since the language intrigued me' (Bird of Passage, p. 67), and it is remarkable to observe in the correspondence his use of Russian grow from brief phrases of endearment to sentences, paragraphs and eventually almost entire letters. This, together with the accounts of his scientific, social and personal life in Pauli's Zürich laboratory at this time, make this one of the most interesting items in the collection.