Full title reads - Napoleon & the Archduke Charles: A history of the Franco-Austrian campaign in the valley of the Danube in 1809.  Given a hundred years or so have passed since publication, and contrary to much spurious marketing hype by other publishers, little has been added to our knowledge of this campaign since Mr Petre put pen to paper. The result is an excellent book verging on masterpiece. The descriptions of troop movements and battles is very clear and concise, the maps are also clear and simple to understand, and the entire text flows well.
I also have the matching 1970's edition of Prussian book.