Do not read this book if you have any interest in German naval strategy or tactics during World War II, nor indeed if you have any interest in an objective appraisal of the life and work of Karl Donitz as a man. This book is undoubtedly well researched, with the co-operation of some people close to Donitz, including his family, but that research is utterly wasted by the author's own cultural prejudices.
There are precious few times when objectivity is allowed a rear its head by the author. These are to be found in the acknowledgements where the author states that he knows that this book will hurt member's of Donitz's family who helped him; in the introduction where the author acknowledges the difficulties that the cultural divide has caused him and in the postscript where the author truthfully reports that other reviews found he displayed "distaste" for Donitz, even "torturing" the evidence against him.... a total want of charity."
The few good words that are said about Donitz almost all come from other Naval personalities, especially his superiors during his rise up the ranks and his contemporaries in the Allied navies. The author even acknowledges that the official histories of the Allied navies are generous towards Donitz, but that does not alter his perspective.
Throughout the book, the author refers to the German struggle against `England' in both World Wars rather than against the British Empire or even Britain. That is central to the author's flaws. The American and Canadian navies are barely mentioned in the book, unless there is an opportunity for criticising them as well! The Empire navies don't seem to exist. Every alleged or real atrocity by U-boats crews is rehearsed with scarcely an acknowledgement that atrocities were also carried out by Allied navies. That the German's may sometimes have been reacting to British or Allied acts, is never conceded.
There is a complete absence of analysis of the actual battles in the Atlantic. These are mentioned at the most superficial, strategic level. Even this level of analysis is corrupted. Unlike Winston Churchill, the author does not allow for a second, that had Donitz managed to have greater influence on German military and naval strategy at the start of the war, then Germany might have won the Battle of the Atlantic.
There is barely a paragraph that isn't laced with a very amateur psychologist's attempt to interpret Donitz's actions, usually as pejoratively as possible, regardless of lack of evidence. For example `photographs of him from the period convey an impression of a man peering out suspiciously from inside his skull as if haunted by the past and wondering whether it was going to blow up beneath him' The author strongly believes Donitz should have received the death penalty at Nuremburg. Many readers will find that this book may be more deserving of the death penalty.