This is only the first 60 pages of a 223-page book; I still have a copy of the original hardcover, purchased from Doubleday's "SF Book of the Month Club" almost 60 years ago.
The book was serialized in a magazine as novellas and then released as the complete edition, so calling it a "Trilogy" stretches the facts past the breaking-point. This first part ends almost mid-sentence, there is no closure, the story has barely begun to unfold.
As to the quality of the story, which normally would be the purpose of a review, it probably deserves 3 stars; McIntosh was an excellent writer, so even though the storyline is simplistic, it moves along quickly, and he manages to hold your attention for the brief time it takes to read these 20,000+ words.
In fairness, Amazon probably doesn't know the packaging here is deceptive, as they also carry the hardcopy edition, which is complete; and the new publisher's name, "Prologue Books," should give us fair warning that this is only the prologue of the actual book. If you want to read the whole thing from them, it'll cost you nine bucks.