I will say upfront that this is not a book to pick up and read cover to cover, and I didn't do that. I have not read every page, but I've read a great deal of it, and I'll be going back to it time and again.
I bought this for research purposes, knowing almost nothing about the Spanish side of the Peninsular wars and being about to write a heroine who was a partisan. This first of all gave me an excellent background into the state of Spain, politically, economically and socially, before Napoleon invade, which was valuable context not only for the effect of the wars on the country, but for understanding why, post-1814, Spain entered a long and drawn out and very complex period of social change and upheaval that really only ended with Franco's death in the 1970s.
It's really well-written and painstakingly researched. It is a scholarly tome, no getting away from that, but it is filled with fascinating little counterpoints to the narrative historical flow - excerpts from diaries, personal stories etc. I had no idea that guerrilla warfare originated in Spain at this time, and absolutely no idea that the Spanish guerrillas/partisans played such a vital role in 'winning' the war against Napoleon and ousting his army from their country. And here's the key point that Fraser makes over and over: the Spanish wanted the French occupation over, that's what they were fighting for and why thy saw it as a revolutionary war; while Wellington and the British army were interested in the 'big picture' - getting rid of Napoleon. Fraser argues, to a degree, that this difference in objectives meant that Wellington used and abused the Spanish armies in their various forms, and that the various governments in the Congress of Vienna afterwards sidelined Spain and its contribution. He is very critical of Wellington at various points, and I don't know enough to argue with him, though he argued very persuasively as far as I'm concerned.
This is a fascinating book. It's dense, it's long, and as I said, far from an easy read, but in terms of the subject matter, it's brilliant, and as far as I'm concerned, it's not only given me everything I needed for my own research, it's thrown open the door to a whole new arena of history that I'm definitely going to be pursuing.