This is a fascinating look back into the history of the Babylon 5 universe, to Earth's discovery of "teeps" amongst their population and the resulting years of turmoil (resulting in the event in the book's title). While Bester is on the cover, he really only comes into it at the very end, in the same way Luke and Leia show up in Episode III.
This is the first of a "trilogy", but there is not great story arc continuing through them; they are just set at the beginning, middle, and end of Bester's life. Greg Keyes is a great author, and while I was not very much into the Psi Corps aspect of B5, I bought these books because he was the author and thoroughly enjoyed them.
I have always been a Babylon 5 fan. This book answered alot of unknown questions from the series and answered a few that I actually had. While I believe non B5 fans would enjoy the book, I do recommend it to other B5 fans.