First a preamble:

There is no such thing as a 'bad review'. This is just an opinion and just one persons opinion at that. Sure, if enough people mention the same things an author might consider looking at that area in their next story. But the overall intent of any review that is not always positive is (at least from me) a hope that the writer, director, star etc would look closer at what was mentioned and use it as a building block and not a stumbling stone. As I said, there is no such thing as a bad review. It is nothing more then opinion.

This is going to be a short review. As I understand it, the last Blackcollar book came out sometime in the late 1980's. That is the entire problem with this story; a generation has come along who has very little idea who the Blackcollars are, or what they are trying to do.
Very little character development is given for the various people involved in the story and that works against it as well. We are told that the blackcollar teams fight Ryqril conquerors, but we know very little about the Ryqril either.
Are they benevolent conquerors who just want to rule others or are they carnivorous creatures looking for a buffet. Sure, many of these questions are answered in the story, but it comes along so deep into it that a lot of people are just going to tune it out long before they reach that point.
Here the blackcollars must go to another conquered world, infiltrate a Ryqril tactical center and gain the military data of an entire sector of space. Now they face their most serious challenge. It could balance the current war between the Ryqril and the human allies, the Chryselli.
But a human agent of the Ryqril has a plan to defeat them, a clone of the blackcollar leaders friend, Allan Caine. The clone is ready to be slipped into the inner circle to spy and return information about the blackcollars to the Ryqril.
Yes, I did sort of enjoy the book even with the acceptance of so much disbelief. Yes, I thought some of the subplots were pretty good if familiar. But, I would not have bought the book. I might have picked it up at the library or a thrift store if I leafed through it, but all in all, I think I would wait for the next Laumer collection.