What woman sang with Leonard Cohen on "Who by Fire"? (on "The Essential Leonard Cohen")

Janis Ian (her birth name is Janis Eddy Fink)

3rd paragraph in Songs section

https://en.wikipedia.org/wiki/New_Skin_for_the_Old_Ceremony

One critic commented:

"New Skin for the Old Ceremony may be Leonard Cohen's most musical album, as he is accompanied by violas, mandolins, banjos, and percussion that give his music more texture than usual. The fact that Cohen does more real singing on this album can be seen as both a blessing and a curse -- while his voice sounds more strained, the songs are delivered with more passion than usual.

Furthermore, he has background vocalists including Janis Ian that add significantly to create a fuller sound. It is no surprise, however, that he generally uses simple song structures to draw attention to the words ("Who By Fire"). The lyrics are filled with abstract yet vivid images, and the album primarily uses the metaphor of love and relationships as battlegrounds."

http://app.audiogon.com/listings/rock-leonard-cohen-janis-ian-new-skin-for-the-old-ceremony-columbia-kc-33167-from-1974-fir-2012-08-18-music-92029-escondido-ca