The paper investigates the expression and translation of the author's textual persona in the popular science text Packing for Mars (Roach 2011). One chapter from this book is translated into Swedish and compared to a parallel translation of another text by Roach, as well as a translation of the novel Shantaram (Roberts 2003; 2007). The specific features under investigation are Roach's use of appositional constructions, first and second person pronouns, and unstandardised direct quotation. The paper argues for the contribution of these features to the expressive, personal and humorous nature of the text, and draws parallels to the genres of journalism and literary fiction. Translation choices are then discussed with reference to Ingo, Newmark, Venuti and others, with an emphasis on furthering the textual persona through an equivalent effect on the reader. The possibility of equivalent effect is questioned, and strategies such as compensation and consistency suggested as solutions when formal equivalents are lacking in the target language.