Question: who wrote the theme song to law and order?
Answer: Mike Post

Mike Post ( born Leland Michael Postil , September 29 , 1944 ) is an American composer , best known for his TV theme songs for such series as Law & Order , Law & Order : SVU , The A-Team , NYPD Blue , Renegade , The Rockford Files , L.A. Law , Quantum Leap , Magnum , P.I. , and Hill Street Blues .