The basic premise is that a new, improved faster-than-light drive is discovered which is thirty times faster than the prior drive, and which permits travelers to reach portions of the galaxy which were previously out of reach. Two superluminals containing five people (including the main character of the series, Priscilla Hutchins) go in search of the answers to four mysteries. The trip is thoroughly fascinating, including believable characters whom the reader can empathize with. The long passages spent on a spacecraft are fascinating and the explorations spark thought-provoking implications. One of the novel’s major strengths though is the sense of wonder which is evoked by the explorations, especially in the origins of the “omega clouds,” which I had not expected to be resolved satisfactorily, but McDevitt did so in a manner which was both fulfilling and thrilling.
Cauldron is McDevitt at his finest writing, more evidence that he is one of the very best storytellers currently working. I recommend this novel highly (moreso if you have read the entire series preceding it.)