Even an anticommunist can potentially make a good book about a communist subject, or even if it isnt it can potentially be read critically to learn stuff.

Ad hominem. Probably a piece of shit, but doesn’t directly tell about the book.

Even reactionary sources can be useful.

I’m not saying these books are good, simply that you can surely do a better job.

Author’s name from the first part?

Try reading Zhovtyi kniaz