Yes, I know I reviewed a book with the same title not so long ago (well, okay, a fair while ago but I've not been posting for a while because I've been busy at college), but it seems to be a popular title. I have actually now read three books with this title, this being the second, and I would class this as the best history of the campaign as a whole from the three.
It's the BBC version, written by Andrew Williams, and proved not only informative with regard to both sides of the story, but also liberally filled with first hand accounts which brought the campaign to life. It's a well produced book, with good organisation of chapters, an excellent section on Enigma, and I didn't notice any typos which is always encouraging. Very readable and enjoyable, it was also informative enough that I used it as a reference source for an essay plan on British incompetence and lack of resources 1939-1941. I was particularly impressed with the focus on the intelligence battle and on the information about the u-boat service from crew members through to the command systems. An enjoyable read as a book and not just as a history book on a campaign you should probably know about, I was certainly impressed. Where it lacks is that it relegates the last two years of the war, after the battle was won, to a single chapter. Certainly understandable, it in no way detracts from the excellent narrative of Autumn 1939-Spring 1943.
In short, if you want to learn a little about the Battle of the Atlantic, a battle vital to keep Britain fighting in World War Two as the island was hugely dependent on imports both to feed the population and to provide raw materials for the war industry, this book is the right one to get. There're good explanations of the important technical points, and a welcome reluctance to use obfuscating terminology that makes you rely on a technical dictionary to understand the text. It's also an interesting read as a book.