Interesting fact about Engels' "On Authority". The only known copy or contemporaneous reference* to it is its publication in an Italian journal Almanacco Repubblicano. Engels' copy of it was never found [1], he never referred to it (nor did Marx-indeed there is little evidence

to suggest Marx was even aware of its existence beyond him also publishing a piece in that journal a year earlier). The piece is well worn within leftist circles only because of its constant citation by MLs against anarchists (and while critiques of anarchism are not unwelcome,

this particular polemic is hot garbage). Anarchists are well aware of its existence and have written probably dozens of responses at this point (I'm extensively familiar with 3 off the top of my head).

* I have searched but have not been able to find any.
[1] I was recently told by a comrade that this is evidence Engels did not think much of the piece either.