The book has everything: tactics, strategy, maneuvers, sieges, escalades, forlorn hopes, sacks of towns and full-on battles. Jac Weller's research for this book is impressive. He has mastered the voluminous records of the period, he has visited every site. His descriptions and detailed diagrams enable every battle to be reconstructed. The reader can vicariously die in the breach at Badajoz or advance with Picton's Division at Salamanca. 
Somehow the real horrors of war do not seem to emerge from Weller's straightforward and clinical prose, in spite of the list of casualties which he scrupulously gives at the end of each action sequence. There are first-hand accounts quoted in the book which go some way to overcoming this problem.