This is the best one volume treatment of the Peninsular War I've read. The sketches, (I can't call them maps), are numerous and useful. The text is clearly written. The reader gets a relatively open-minded view of Wellington the general, and some of his flaws and indecisions are clearly shown. One thing that Gates attempted is to place in perspective the amount that the Spanish forces contributed to the Allied victory. It was a good deal more than the English speaking world credits them with. There's a chronology that is a good mechanism for further research and cross-referencing . If you only get one book this is it.
But do not get this edition, if you plan to use the book as a reference. The binding was incredibly poor, with the signatures easily torn open along the spine, and the paper is very stiff, battling the book frame you have to use to keep the thing open. I hope the following editions, and there are a number of those are physically easier to handle. ( )