Anyone else find it absolutely fascinating; that there was a possibility of staring down fascism in Europe, the refusal of the British and French governments to even arm the elected government...
Orwell's magnificent Homage to Catalonia, the International Brigades; both inspirational in what they represented but also glossing over the brutality of Stalinist communism.
Less obviously, I'm a massive fan of Judith Keene's book on foreign volunteers for Franco "Fighting for Franco" - it's available on Amazon, and I'm sure available more cheaply elsewhere. It's an outstanding and fascinating book.