Overall, this book delivers on the promise of a dive-themed thriller. It's not the world's greatest thriller, but you definitely get what you paid for. The plot is intriguing and fun, the characters are well-defined (though I had difficulty telling some of them apart at the beginning). It was a quick read and I enjoyed it.
I came to this book as a fan of the author, Jason Heaton's, podcast "The Grey Nato", curious to read his first novel. He clearly took to heart the "write what you know" advice – diving, watches, Sri Lanka, Land Rovers and Land Cruisers, winter in the MidWest, and even being left-handed. While perhaps distracting at times, as a fan, it was fun to get these little "shout-outs" sprinkled throughout the novel. Yet, while I generally enjoyed the writing style, there were places where the prose was a bit clunky, particularly when the author needed to provide technical background information (e.g., on saturation diving). The style would jump from a narrative to a non-fiction, informational tone and back. I look forward to reading Heaton's follow-on novel, "Sweetwater".