This reviewer had previously read (and favourably reviewed) Marc Milner's "Battle of the Atlantic". This earlier book of Milner's is a more detailed study of the engagement of the Royal Canadian Navy (RCN) in that huge conflict up to mid-1943, the turning point in the campaign.
It is definitely a more specialised book than "The Battle of the Atlantic" and will be of greatest interest to more serious students of maritime conflict in World War 2. The book relates the huge war-time expansion of the RCN (it grew 50-fold in 5 years) and the inevitable strains and shortcomings that such an expansion rate was bound to cause. But by mid-1944 the entire the whole North Atlantic route, from New York to the British coast, was an exclusively Canadian operation. Before gaining their pre-eminent position in that theatre of war however, the RCN had undergone some severe trials and tribulations, which the author has researched very thoroughly. This reviewer found it an absorbing read.
It is, however, a less mature work than "Battle of the Atlantic" and I would recommend reading the later book first. This is a good book, but not as outstanding as "Battle of the Atlantic".
In one sense this book is much more about the expansion of the Royal Canadian Navy than about the Battle of the Atlantic itself. Thus it will appeal to the serious student of World War II. For example there are some graphic descriptions of the inadequacies of the ships, their equipment, and the consequences of lack of training. However, I believe that in setting out the details of a traumatic expansion there are clear lessons for all organisations planning expansion. You can't grow any organisation rapidly without the tensions showing somewhere. Something somewhere has to give. Those outside are always ready to criticise, especially when they are relying on you. There will often be a range of views of how expansion should be managed. But did the Canadians do a good job? If you want details of the Battle of the Atlantic, look elsewhere. But this is a fascinating insight into an aspect of the expansion of the military machine during the World War II. Compare this with Brian Lavery's works on the Royal Navy during the World War II.