Building upon the review of Mine Were of Trouble, I would like to offer a list of books to help cradle English speakers get a grip on the War in Spain.
I am compelled to offer three framing comments at the beginning.
1. First, works about the War--even in English--are inevitably politicized. The War inspires strong passions in the Western world to this very day, and the historians who write about it are no exception. Even the act of toning down one's reactions and trying to assess the facts objectively, in a comparative framework with other ideological conflicts, is subject to accusations of bias. One is accused of (or lauded for) being pro-Republican or pro-Nationalist, pushing a narrative. And readers can be sucked in as well.
The necessity for the reader is to recognize the historian's biases and his own and to engage in periodic reality checks.
For example: is the author presenting one side's atrocities in a different light than the other's? Pro-Republic authors frequently have a tic in this respect. This is best seen in what I call "the church caught fire and the priest died" pro-Republic depictions of the Loyalist pogroms of 1936.
Thousands of Catholics--laity, clergy and religious--were targeted and slaughtered by Republican forces in the wake of the rising of the generals.
In a grand irony, this butchery turned the officer corps' rising into a Catholic crusade. The initial proclamations of the Generals explicitly spoke of restoring order to the Republic and respecting its institutions, including the separation of church and state. And there really is no evidence that such were insincere.
The massacre of the Faithful changed all of that, with Catholics of every class and region under Nationalist control becoming fiercely pro-Nationalist and swelling the ranks and resources of the Generals' forces. This forced the Generals to change their tone fairly quickly: by autumn of 1936 the Crusade for Catholic Spain was on.
The slaughter is acknowledged by Republic-favoring historians, but it is often described in the passive voice, occurring as opposed to directed--spasmodic, spontaneous and unforeseeable--definitely not the systematic killing of Nationalist firing squads.
Um...no. The Republic threw open the arsenals to anti-religious fanatics and what followed was entirely foreseeable. Anti-religious rages had been blazing, albeit at a much lower level, for months before the War. What did they expect when they handed the militias military weaponry and the color of law?
It is true that members of the Republican leadership tried--sometimes successfully--to intervene to save people, and eventually the pogrom wound down. But this was due as much to the flight of Catholics to Nationalist territory and the sending of the fanatical militias to the front lines to do some actual fighting against people who could shoot back as to policy.
Bottom line: watch how each side is depicted for similar actions. Because pro-Nationalists get their passive voice on as well.
2. Secondly, have a note pad handy. It is taken me years to get the names of the various personages straight. When you first run across someone who appears to be a major personage, write down his or her name and political affiliation. Gil Robles was not Calvo Sotelo--that took me a while, for some reason.
And do the same for the major factions. Because, you see, there is usually a very unhelpful Spanish acronym, or a puzzling adjective before an otherwise understandable noun, which describes the welter of contending organizations.
Trust me: you do not want to confuse the CEDA with the CNT, the PSOE for the PCE or POUM, or the Alphonsine monarchists with the Carlist ones, etc.
3. Learn Spanish.
At least the pronunciation--you are much less likely to sound like an idiota. Canada and Cañada are...different places after all. But getting at least a tentative grip on the language will help you see the mindsets better, too.
With those advisories in hand, on to the recommendations:
1. Hugh Thomas' one volume history. Still the gold standard. First published in 1961, and considered fair enough by the censors to be published and sold in Franco's Spain. Genuinely even-handed, even if it focuses more on the Republic. Which is actually fair enough in and of itself: the dysfunction of that half of Spain necessitates more words.
2. The Victorious Counterrevolution by Michael Seidman. Absolutely essential. It could also be entitled "How the Nationalists Won." A searching evaluation of the factors that led the Spanish "Right" to win their civil war when similar forces in Russia and China lost theirs.
Bottom line: no bleed-out from a previous war (World Wars I and II, respectively), better logistics, better use of resources, much less corruption and infighting. Nationalist soldiers ate well and civilians had a functional currency which meant they managed to do the same. Foreign assistance was not as decisive as pro-Republic historiography suggests--the Nationalists just did better with theirs than the Republic did. Alas for Spain, the regime would founder economically after the War and only start to get its legs underneath it with American aid and the abandoning of quasi-fascist demands for autarky.
3. Martin Blinkhorn's history of the Carlists in the Second Republic and the War. At least you will understand how one of the major members of the Nationalist coalition thought and fought.
4. Franco and Hitler by Stanley Payne. Payne is the dean of American historians on all things Spanish, but the Civil War is his specialty.
Payne is often accused of being pro-Nationalist--and to be fair, he is a friend of Franco's daughter, Carmen. But he is also a consistent puncturer of pro-Franco mythology created by the regime, not least of which were their attempts to retcon Spain's relationship with Germany during the Civil War and World War II. Contrary to Cold War mythmaking, Franco wanted to join WW2 on the side of the Axis. But neither side could get past this negotiation stalemate: Spain had not recovered from the Civil War and needed resources before it would commit to a declaration of war, and Germany wanted Spain to commit to a declaration of war before it would send resources. The most Payne will concede to the regime is that it had a very distorted understanding of Nazi war aims and Hitler's plans, looking through the outdated experience of German aid in the civil war. It did not understand what Hitler's completed new order would mean, and how small a place was planned for Spain within it. Spain's escape from destruction in World War II was mostly lucky, owing more to Barbarossa consuming Germany's focus--and eventually its armies--than it did to cannily fending off Germany's overtures. Though there were definitely pro-Allied elements in Spain who helped.
5. Finally, a novel: General Escobar's War. A fictionalized account of the devoutly-Catholic General Antonio Escobar Huertas's actions during the Civil War, it is genuinely moving. Escobar stayed with the Republic despite his brother and youngest son going over to the Nationalists, and he was executed by the victors in 1940. It created quite a stir when it was published in 1982, as it does not spare either side.
I have more suggestions, but the above should occupy you for a while.