I have 3 different versions of this book.  This one is a 1st edition import.
Petre's five volumes cover major aspects of Napoleon's Campaigns. For the modern reader his prose might seem a little dated at times, but he is a spirited writer none the less. Since he covered many of these battlefields in person, Petre likes to give detailed analysis of the ground and terrain that was fought over and fold out maps are included. Petre likes to have the reader follow along as the Corps and Divisions march. 

Where the author excels is in his battle scenes. I doubt one will find a better Eylau than here. He draws upon several contemporary authorities from both sides including the Prussians who did extensive studies later in the 19th century of these campaigns as part of their developing general staff system. You will also get plenty of details on lesser known actions of the Campaign besides the two major battles of Eylau and Friedland which are well known. Petre tries to get into the head of those making the decisions and with his often detailed notes contained within the body of the text will try to explain why certain courses of action were embarked upon, especially when these were controversial. He provides some good tactical details here and there pointing out that both sides deployed their battalions in the first line and supported them with a close column in the second line between the intervals. This shows us that both the French and Russians in this period were fighting in much more linear formations than they would in 1812 and later. Admittedley as the armies got larger the quality of the soldiery declined. For the French this would certainly be so as this was the last of their Austerlitz veterans who knew their drills. The conscripts who followed increasingly were formed into those large columns made famous in later battles and in the Peninsular.

As an English historian one can tell that his bias is not in favor of Napoleon's actions all the time. In this respect he would agree with how some recent historians have taken a more critical and less heroic approach toward L'Emporeur. Several times he attributes the mass suffering of all those around him to his own vanity, and despite how horrific things became during this campaign, the great man never let it phase him. All was simply a mathmatical process that could be modified and changed as needed. Petre gives him his due in that regard, ackowledging his genius in managing huge amounts of detail all at once. But it was a cold and pitiless genius that took no account of how those suffered from his decisions. Those who are fans of Napoleon should take note of this at times.

The 1806-07 Campaigns were the toughest the French had fought so far. In the Russians they found a tenacious enemy in terrible winter conditions. Napoleon would remember his Polish Campaigns when planning for the epic 1812 venture. 

For the true Napoleonic fan Petre's books remain classics to read today. This and the other books in his series on the Napoleonic Wars in Europe are must reads.