I picked up this book for two reasons. First, the TV show FlashForward used this book for inspiration. Second, the book is by Robert J. Sawyer, who wrote several other books that I enjoyed (including Hominids and Humans -- I haven't read the third one in this trilogy though).
If you have watched the TV series, don't worry. The book is only the inspiration; there is really nothing in common between the book and the TV show, other than the flash forward itself. In the book, people see 21 years into the future; in the TV show, it is six months. The book is set in and around the large hadron collider at CERN; the TV show is set in the US. As you can guess from the setting, the book resolves the cause of the flash forward very early on; the LHC experiment combined with some cosmic activity lead to the flash forward. The book focuses on the scientists involved in the LHC experiment, on the physics of the incident, and on the philosophies of free will and predetermination.
One thing I like about Sawyer's book (this one included), is that he bases the plot around proven science, but takes it further. His books always make me want to read more about the science he uses. In this case, I spent a few hours reading about the large hadron collider and the search for the Higgs bosun particle.
Although this book is heavy on the science, I would recommend it highly for those who like science ficition set in (at the time it was written) near future versions of our own world.