Clue: Songwriter is honed after working on first of musicals (8)
Answer: SONDHEIM
Explanation: Definition: Songwriter
 **Anagram of**(… after working) IS HONED **placed above**(on, in a down clue) **1st letter of**(first of) "musicals".
Answer: …, Stephen, composer, songwriter and lyricist who was a leading figure in musical theatre.