I'm not sure that I'd read any of Orwell's non-fiction of any length before. It is a great personal account of taking up arms in an idealistic struggle, and finding that the grim realities are not especially glamorous, and that indeed the political leadership is more concerned with internal manœuvring for power on their own side than with actually, y'know, winning the war against Franco. Orwell is particularly bitter against the Communists, who were by his account instructed by Moscow to sell out genuine revolutionaries in order to safeguard the USSR's wider geopolitical position, and it's an important and vehement reminder that most of the Western Left, back in the day, were very hostile to the Soviets. His descriptions of the reality of fighting are vivid as well, both inching ground off the Franco forces in the mountains, and the internal fighting up and down the Ramblas (or more accurately between hotels and the Barcelona telephone exchange) when the other shoe finally dropped. It reminded me of accounts I have picked up from more recent conflicts in the Balkans and Cyprus - not from the peacekeepers but from primary combatants. There's a fascinating sub-plot about the use and abuse of information to shape the received narrative of what is going on during wartime, but that's not the primary focus here; Orwell addressed it pretty well in both Nineteen Eighty-Four and Animal Farm. A great and short book, which everyone should read.