John Barry's music
All movie buffs know that one of the things thst made "The Third Man" so memorable was the dazzling zither music of Anton Karras. I would argue that one of the things that elevates "Body Heat" into greatness is John Barry's wonderfully seductive, sultry, and tension coiled score.
The first time I saw this movie the jazzy haunting theme played on saxophone at the opening and end of this movie reverberated with me long after the movie was over. The unspoken scene in which Ned Racine breaks through the glass door to Matty Walker's home depends crucially on the hushed menacing tones of Barry's score which suddenly erupts into a renewed version of the main theme. The music brilliantly reinforces the drama of the scene.
Barry's score, much overlooked in my view, is well worth buying on CD in its own right and deserves a lot of credit for making this movie into something truly special. "Basic Instinct" doesn't even come close dramatically or musically.