This is the first volume in a four-book series. The book ends at a point where many readers (especially plot-oriented readers) will want to know what happens next. A large part of the book is devoted to making readers familiar with the characters, with the plot slowly sneaking in through most of the book. Perhaps, character-oriented readers would find it easier to read this as a stand-alone.
The story involves a cylindrical space habitat large enough for landscaping and various buildings spread out through the structure. But it's original intention was to be a starship. A cosmic string has come close to the solar system. [A cosmic string is a theoretically possible object that may have resulted from the Big Bang. For brevity, one might compare it to a long 1-dimension black hole-like object.] According to the story, a close encounter with the cosmic string will allow them to travel to the Tau Ceti star system in a matter of hours.
The plot which emerges involves international tensions on Earth, and the resulting pressure / coercion from the US to convert the starship to an Earth-orbiting military / spy base for the US. The starship was built using funds from a number of countries, but the US was the largest contributor and the country most used to being able to make others do as it wished. While opinions on this issue vary among the people on the starship, most of the central characters are scientists oriented to carrying out the original mission of interstellar travel in search of alien life. However, there is at least one American spy on board and, it seems, another saboteur.
The book ends as the starship arrives in the Tau Ceti system and detects signs of civilization.