Admittedly haven’t read this yet, but according to Anark, this is one of the best books on the subject of the Anarchist movement in the Spanish Civil War, and goes into detail of some missteps and failings they fell into, which we can hopefully learn to avoid.

Apparently, Anarchism and Workers’ Self Management in Revolutionary Spain by Frank Mintz is a good companion book as well, and is available on Archive.org!

Perhaps not essential reading, but if you’re a history buff and have a particular intrigue in Anarchist Spain, then hopefully you’ll find these two books useful and interesting. :)