BLUE marks the culmination of Mitchell's early, traditional singer/songwriter period, and it is one of the very best albums of that genre. Though she was already beginning to experiment with elements of pop and jazz, BLUE focuses on Mitchell's skill as a folk singer, showcasing her reedy, expressive voice in duet with her piano or guitar. The arrangements on the album--which feature keys, dulcimer, bass, and assorted percussion--are spare and tasteful, so much so that it is easy to overlook their sophistication.