18th Century Guy: OK
Arthur: I hope you enjoy the book and I have more on Spain and Portugal on the way - along with 1711 Russians and Ottomans.
On Marlborough - obviously his name is important to material on this as you suggest. Also as you suggest unless you know something about this theatre you are unlikely to know the other names involved. But this theatre is a about Marlborough and vital to his story.
As you say he never set foot in Spain or Portugal but he was effectively the supreme commander, or at least the most important commander, of all the anti French forces. He was the main driving force in strategy generally. The direct superior of the British forces in Spain/Portugal and paymaster of most of the rest. He didn't make the day to day decisions but he was largely responsible for the rest and the most important military parts. For example you could argue [but I wouldn't] that Galway lost Almanza because he was heavily outnumber. This would be Marlborough's fault because didn't send enough troops to Spain.
So I wold argue that the armies there are 'Marlborough' in the military sense because he is effectively the military leader of the Confederates. But more importantly, and this is the sense meant in the book, it is Marlborough's last chance in Spain politically. He is leader of the British 'Hawks' and at this time they are steadily losing influence. A key part of their doctrine was the slogan 'No peace without Spain' and Marlborough was being attacked politically for his failure to capture Spain for the cause. The failure of the 1710 campaign and loss of most of the British troops in this directly lead to political action against Marlborough which within a year lost him his political/military posts and everything that followed this.
So this campaign was politically Marlborough's last chance. Because of the centrality of the 'No peace without Spain' idea to the Hawks the Spanish theatre is arguably the most crucial theatre of the war. Certainly it was this theatre that was the key to the events that brought Marlborough down and settled the war.
In any case I hope you like the book if you get it. The good news is that both sides get 'kick butt' in a fairly action packed campaign. There are 2 Confederate victories, 3 Spanish victories and 1 successful French siege - plenty for every one
