Sometimes. Many promos use excerpts from commercially available music, although some are scored with original tunes and are unavailable.
As for the music featured in programs, they are usually credited in closing credits, although sometimes producers may withhold the information in anticipation of releasing a compilation CD as was done with the first season of The Sopranos. Whenever possible, we will provide the music credits and track information along with the corresponding iTunes link as part of the episode information for that particular program.
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