Loved it! This book was a fascinating overview of the punic wars concentrating on the 2nd war and the battle of Cannae. O'Connell takes the reader briefly though the history's of both Rome and Carthage to establishes both societies outlook, structure, and political views. The battle of Cannae itself is a small portion of the text. Instead O'Connell spends most of the pages developing the scene for the battle (so that it is understood by the reader in its true context) as well as the aftermath and results of the battle and, in general, the 2nd punic war.
The book is written for a history buff, not hardcore historians. O'Connell has a storytelling style mixed with his analysis. He quotes ancient historians such as Livy and Polybius, and throws in opinions of unnamed "modern historians" (especially when it seems the moderns and ancients disagree). If your a history buff like me who read this on the couch at night, this book is for you. I already new a fair amount about the punic wars but still learned a lot. If your a history student it might be worth reading for context.
The kindle edition of this was good. Only downside is that you can't easily flip back to the maps of Italy and Iberia. Overall two thumbs up!