There are a few things that Hitler and Stalin shared, despite the obvious differences. Both men began their lives deeply committed to their faith, and considered life as clergymen, before turning on the church. Both had doting mothers, and fathers who beat them mercilessly. Both may have worked as police spies inside the very political parties they would later lead. (One of those is well-documented; I’m working on the other one.)

Both men presided over mass murders on an unimaginable scale and are responsible for the deaths of millions of innocent victims. Together they bear responsibility for Second World War — the greatest catastrophe in modern history.

And both were voracious readers.

But while Stalin seemed genuinely interested in a wide range of subjects, Hitler often skimmed books, noting only the parts that reinforced his pre-existing beliefs. He also showed a (perhaps unsurprising) interest in the occult, and little interest in actual science. As Timothy Ryback shows in this thoroughly researched book — he actually checked to see which of Hitler’s thousands of volumes were actually opened, let alone read — Hitler had books by his side right up until his suicide in the Führerbunker in 1945.