Malatesta is the anarchist who most clearly differentiates anarchists from marxists, while recognizing what works: specifically anarchist orgs, participation in unions, working-class self defense. He invented modern anti fascism. Guy doesn't get enough credit.
Anyways, in this one, he calls for anarchist participation in the trade union movement as anarchists. He argues that while unions are a prerequisite for revolution, they are an insufficient organ for it.
While the Italian anarchist revolutions in the 30s and 50s ultimately failed, they came closer than revolutions in anywhere in post-war Europe besides France and Spain, and should be recognized as an essential part of our revolutionary heritage. Who's to say if the Partisan movement would have been a quarter as strong without them.
Anarchists must recognize the usefulness and the importance of the workers’ movement, must favor its development, and make it one of the levers for their action, doing all they can so that it, in conjunction with all existing progressive forces, will culminate in a social revolution which leads to the suppression of classes and to complete freedom, equality, peace, and solidarity among all human beings. But it would be a great and fatal illusion to believe, as many do, that the workers’ movement can and must on its own, by its very nature, lead to such a revolution. On the contrary, all movements founded on material and immediate interests (and a mass working-class movement cannot be founded on anything else), if the ferment, the drive and the unremitting efforts of men of ideas struggling and making sacrifices for an ideal future are lacking, tend to adapt themselves to circumstances, foster a conservative spirit, and the fear of change in those who manage to improve their conditions, and often end up by creating new privileged classes and serving to support and consolidate the system which one would want to destroy.
Hence the impelling need for strictly anarchist organizations which struggle both inside and outside the trade unions for the achievement of anarchism and which seek to sterilize all the germs of degeneration and reaction.