Differences between book and movie (spoilers)
In the book, Ms. Birdie actually went to live with her sons in Florida and although in the book she wanted to come back and finally she was set to come back, Rudy had already packed his belongings and left.
In the book, Rudy is actually hired as a paralegal for a law firm using him just to get the Black case.
Rudy is questioned by police about burning that law firms building down and since he is flat broke and needs a lawyer, Prince takes him to see Bruiser and that is how he starts working there.
The jury trick was actually used on all jurors they did not like. Deck talked to Rudy about talking to jurors they did not want. Obviously though, the one they really didn't want was the only one they pretended to contact (Randy Travis).
The Riker family calls with death threats to Rudy and police station after they find out Cliff was killed (they were described as drunkards and white trash).
A law professor in Memphis was the one that helped Rudy develop the case against Great Benefits. A lot of his lines in the books are spoken by Deck in the movie ("street surance", etc)
The trial was actually easy for Rudy in the book. He nailed everyone and Drummond never had a chance.
They had to hide Kelly in an underground shelter for abused women after filing the divorce, instead of staying with Ms Birdie.
Drummond is not at the deposition at Great Benefits in Cleveland.
Bruiser is never heard from again after he skips town. Although later on, Deck says he had 4 million in cash hidden and would give Deck 10% of the cash if he got it safely to Miami (there was no call about stolen evidence)
Bruiser was described as a fat 300 pound guy (surely you wouldn't have pictured Mickey Rourke, although he was great)
Buddy Black never received a picture frame of Donny Ray and never showed it in court crying "why"
Donnie Ray had a twin brother who was an exact match for a bone marrow transplant
Drummand actually apposed having Rudy argue the motions in the courtroom (before he got his license). In the movie, he wanted Rudy too argue the motions, so he stood as the witness.
Deck never got up and started questioning CEO Keely because Rudy was late.
All in all though I thought it was a great book and I think the movie was really good as well.