Jack McDevitt finally reveals the origins of the mysterious Omega Clouds, first introduced in "The Engines of God," and explored further in "Omega." "Omega" promised answers, but all it really told the reader was what the Omega Clouds did, a little about their technology, and some further exploration of past races wiped out by encounters with the right-angle hating storms.
McDevitt fulfills the promise of explanations in "Cauldron," although like most of the great mysteries that McDevitt likes to pepper into his sci-fi novels, the answer is not as intriguing as the question. The real meat of the story here is his tale of a future human race that has the ability to navigate among the stars, but is quickly losing the interest. Much like the modern day space program the technology is amazing, but it has little practical use. At the opening of the novel the only people still interested in traversing the stars are tour groups to Alpha Centauri.
Unfortunately, McDevitt never really explores the implications or the solutions to such a state. He provides a miracle technology which allows the human race to go farther and faster than the previous hyperspace technology, but at the end of the novel they've explored deeper into the cosmos than anyone in his sci-fi universe and still haven't found anyone worth talking to.
That's not to say it's a bad novel. McDevitt's strength is at writing adventures in the shadow of a great mystery, and the adventures here are thrilling and memorable. He has more of his trademarked alien ruins and derelict space ships, and the story is gripping as long as danger is looming. Even the finale, while lacking in what I think should be a considerable amount of awe, is exciting.
McDevitt never does well when it comes time to shine a light into the dark corners he creates in his narratives. In "Eternity Road" he tossed off the explanation in a single sentance, without any further comment. Here, he gives it a bit more heft, but it still left me with a feeling of "that's it." The mystery of the Omega Clouds was drawn out over 3 novels, and referenced in the background of at least 2 others, but the final revelation just seems a let down.
I don't want to spoil it, but I will say that McDevitt seems to have attempted to answer not only his own mystery, but one of the great rhetorical questions of Star Trek history. He does have an answer, but it boggles my mind much more upon contemplation than it did when reading it.
However, aside from the unsatisfying mystery, the novel has plenty of adventure and space opera-esque thrills. Like all McDevitt books, as long as the biggest mystery answered is how to escape from the monster, it more than delivers.