This is the authors 5th book in her Endurance series, and is by far (to this reader anyway) the most riveting, exciting, surprised filled story with some magnificent characters, and her best work into this world of life on an enclosed space ship traveling from earth to it's new destination 1,000 years away. We have here thousands of people who have never known life on earth and for generations have lived on this "ship" traveling through space. So long that some have forgotten the truth of their beginnings and this has started one of the most dangerous groups among them, "the cavers." Because what many think is a one time dangerous incident, a group of friends gather to hear what happened when one of there own is forced to "save the ship" and what she sees has excited them to discussions. These discussions are mainly brought on by a stranger to their group but not unknown to those who live in this world, and brings them to startling revelations. This starts an on-going learning and teaching experience for them and their leaders, which unfortunately brings dangerous action from the "cavers." I want to say so much more but I do my best not to write spoilers, but to give you the excitement (or not) of how the story makes me feel. And let me tell you that this story makes me gives me such strong feelings of awe, understanding and the ending is nothing short of astounding. If you are a Sci-Fi fan you cannot, must not let this book pass you by much less the entire Endurance series. You can read them individually and they'll still grab you, but I highly recommend you read the series as they were written in order to better understand the centuries these people have lived in this enclosed world and how and why changes occur. I tell you this world the author has given us is amazing and jam packed with excitement and surprises. Go get your copy now, no not just grab, RUN and get it, you won't be sorry.