The book is part of an umbrella title called the Lost Years, various Star Trek novels that serve as prequels, covering parts of history not shown or talked about on-screen. Bennett's focuses on Captain Jean-Luc Picard, covering about eight years of time, starting with the destruction of his ship the Stargazer, and ending just before he takes command of the U.S.S. Enterprise.
The book deals with an event that affects the galaxy, with literally trillions of lives at stake. The main alien race, the Manraloths, have technology thousands of years ahead of the Federation's, and it borders on super science. An example is using the event horizon of a black hole to store information for virtually all eternity. The technology could have been used as deus ex machina, but Bennett presents it with hard science and in the end, the technology doesn't sound so far-fetched.
Most of the TNG regulars make an appearance in the book, the big exceptions being Crusher, Wesley, and Riker. When Data is recruited for Picard's mission, I was taken aback, thinking the author just wanted a way to bring the characters together; I'd always imagined that the main bridge crew hadn't met before the events of the pilot episode Encounter at Farpoint. However, Bennett points out that most starship captains can pick their command crew, so it makes sense Picard wouldn't just pick his officers from reading their file. Trio and Data have significant parts later on the story, and there are appearances by Yar and Worf. While they seem just thrown into the story at first, their reasons for meeting Picard before serving together on the Enterpise come together nicely and doesn't feel forced. Many characters from various episodes make appearances or are name-dropped, but if you don't know them or forgot about them it's okay, a working knowledge of TNG isn't needed to enjoy this book.
The focus is on Picard and his feelings over losing the Stargazer and his reluctance to rejoin Starfleet. The book tries to cover the journey from Picard the fun explorer to the stern Picard we meet at the beginning of TNG. Bennett does an adequate job and most of the time I could hear Patrick Stewart's voice as I read Picard's lines. Data's lines were spot on, in my opinion, as were Guinan's. Bennett does a little more telling than showing when it comes to characterization but I think he did an adequate job of Picard's journey as a character.
All in all, this a good book and one worth looking into if you're a Picard fan. It gives us another view of his character and an epic, cosmic mission to save the galaxy.