By this I mean the Spanish Civil War that began in 1936, not the First Carlist War in the 1800's. If anyone has any books that argue the different viewpoints, that would also be much appreciated.
Out of deference to the moderator's comment (and my own desire to avoid getting too bogged down in a very big question...), I'll limit myself to addressing the last element of your question about further reading. It's a controversial, complicated issue, which has been addressed from many different methodological and political perspectives. A sample of such perspectives on the lead up to war can be found in:
Gabriel Jackson, The Spanish Republic and the Civil War, 1931–1939 (Princeton, 1965)
Fernando del Rey Reguillo, The Spanish Second Republic Revisited: From Democratic Hopes to Civil War (1931– 1936) (Brighton, 2012)
Stanley Payne, The collapse of the Spanish Republic, 1933–1936 (New Haven, 2006);
Paul Preston, The Coming of the Spanish Civil War: Reform, Reaction and Revolution 1931–1936 (London, 1994).
You can also find relevant discussion in classic overviews of the war such as Hugh Thomas, The Spanish Civil War (London, 2003 (3rd ed.)). There's also a (now somewhat dated) bibliographical survey in the introduction of Paul Preston (ed.), Revolution and War in Spain 1931–1939 (London, 1995).
Edit: Forgot a more recent bibliographical survey by Ruth Mackay, which makes special mention of 'revisionist' histories of the civil war and its origins:
Ruth Mackay, ‘History on the Line: The Good Fight and Good History in the Spanish Civil War’, History Workshop Journal 70 (2010), pp. 199–206.
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