For what audience is this book written for? And how can you tell? What 2 quotes back this up?
The book is clearly written for a wider audience than just academic historians and, indeed, fits in to the wider body of Stephen E. Ambrose's work which does much the same. One way in which it might be possible to make some claim of this is via the referencing system in the work. Part of the charm of Ambrose's work is that he brings the past alive for the non-specialist reader such as when he claims of Merriweather Lewis's mother that she 'grew a special crop of herbs' in order to produce medicine for her children and was 'known far and wide for her medicinal remedies'. Firstly, Ambrose does not directly reference these claims in order to establish precisely where he has got the information from, one of the conventions of the academic historian, something done via a rigorous process of footnote references. However, a general readership, reading on the back cover that, by 1996 when this book was published, Professor Ambrose was an eminent professor at the University of New Orleans and author of many other critically reputed works of history, would be happy that his authority was such to allow him to make these claims without referencing. This is not, of course, to claim that Professor Ambrose's work is anything other than well researched. However, close referencing can make a text dense and unreadable, something that Ambrose was clearly trying to avoid for a general readership.
One might also claim that the style of Ambrose's narrative is also that of a popular historian. Take, for example, Professor Ambrose's comments about Lewis's father's death and how it relates to eighteenth century concepts of mortality. Ambrose writes that 'People in the late eighteenth century were helpless in matters of health' before going on to write in general terms about how the presence of mortality and the acceptance of the near presence of death in a world without reliable medicines shaped a different sense of one's life than in the modern world. Ambrose, more than a specialist academic historian, is prone to this type of narrative intervention where he effectively 'translates' the eighteenth century mindset for a modern reader, making the past modern and accessible to us. This makes the work highly readable but is a less marked trend in more classically academic works. One might cite the fact that the book was a New York Times best-seller on its publication in 1996 as a mark of its success in this aim.