The Book of Fate by Brad Meltzer

"In six minutes, one of us would be dead.  None of us knew it was coming..."

So says Wes Holloway, a once cocky and ambitious presidential aide, about the day that changed his life forever.  On that Fourth of July, Wes put Ron Boyle, the chief executive's oldest friend, into the presidential limousine.  By the time the trip came to an end, Wes was permanently disfigured, and Boyle was dead, the victime of a crazed assisin.

Eight years later, Boyle is spotted, alive and well, in Malaysia.  In that moment, Wes has the chance to undo the worst day of his life.  Trying to figure out what realy happened takes Wes back to a decade old presidential crossword puzzle, mysterious facts buried in Masonic history, and a two hundred year old code invented by Thomas Jefferson.

If your looking for a good conspiracy book, you will probably enjoy this book.