In 2012 Paul Preston published The Spanish Holocaust, a devastating account of violence before, during and after the Spanish Civil War. There, he showed in great detail how much of the violence on the Franco side had been driven by conspiracy theories – above all, concerning Jews and Freemasons. In Architects of Terror, he returns to this subject, and his account is just as shocking and fascinating. Moving across biography, micro-history and narrative history, Preston tells various stories from post-1920s Spain that reveal how a succession of frankly unhinged conspiratorial ideas lay behind Spanish fascism and the brutal violence that stretched across the country in the 1930s. It is a veritable rogues’ gallery, full of intrigue, double-crossings, jealousy and almost unimaginable levels of racism, anti-Semitism and misogyny. Using his mastery of this highly complicated period of Spanish history, Preston shows how the massacres, brutality and dehumanisation of the enemy for which the period is remembered were built on a tissue of lies and invented plots. 

Preston’s book moves at great pace and is filled with telling details. He has an eye for an anecdote, but always keeps the bigger picture in mind. In a chapter entitled ‘The Policeman’, we hear about the extraordinary life of Mauricio Carlavilla, a mediocre cop, sometime spy, author and occasional agent provocateur who seems to have invented a parallel life for himself alongside his real one. Carlavilla became well known (although he often wrote under a pseudonym) as the author of a series of deranged but bestselling books, mainly about Freemasons, Jews and homosexuals, all of which he connected to communism and the Left more widely. His texts painted a lurid picture of a series of plots to undermine Spain as a nation, destroy its Christian identity and take over the world. Franco himself was directly influenced by such publications and their idea of a ‘masonic super-state’ that supposedly ‘controlled the world’s press and radio stations’. The fact that there were only around six thousand Jews in Spain at this time seems to have made no difference at all to the power of these ideas. Strikingly, Franco continued to believe in a Jewish–Masonic plot after both the Spanish Civil War and Second World War had ended, while simultaneously claiming that he had somehow saved Jews during these conflicts. One of Carlavilla’s best-known books, Sodomitas, which detailed supposed connections between homosexuality, communism and anti-Christian conspiracies, was published only in the 1950s.

In a chapter entitled ‘The Priest’, Preston looks at the life and times of another major influence on Franco and his associates, the clergyman Juan Tusquets Terrats. One of Tusquets’s self-appointed tasks was to draw up elaborate, and largely fictional, lists of Freemasons, which were used as pretexts for murdering