I picked this up as a brain-rest re-read.  I love the story -- far-fetched things keep falling into place for an amazing plan to unfold.  The narrator is credible, the justice system is predictably dense and cruel, eventually the good guys win.  As Grisham's afterward says, "no research at all was done ... but even a lazy author has to hang his hat on some facts."  I think he had fun doing this -- Hope so; I sure had fun reading it.