Bobcat:
The Watchtower, January 15, 2015 issue (p. 29, par. 6), briefly quotes The New Interpreter's Dictionary of the Bible. As you know, the WT does not quote the full sentence, nor gives the context behind the quoted words. There is interestingly, a Section A with the subtitle, "Authorship, Date, Reading," which the Society did not touch.
However, the quoted words do appear on page 349, under Section "B. Poetry of Love." This is what it says (full paragraph):
The love story that is the Song is, in point of fact, not a story at all, or at least it is not told as a story--though that story, the story of the love between an unnamed boy and a girl who only belatedly gets called ‘the Shulammite’ (6:13 [Heb. 7:1]), most assuredly lies in the background of the poems that make up the Song. But the poems themselves are lyric poems, where things like plot, story, narrative development, and character are not really of prime interest, and if they occur at all are deployed, ultimately, to specifically lyric ends. The poems of the Song literally sing about love and its ‘many splendored’ affects, good and not so good, in a non-narrative kind of verse that poets East and West have been composing for millennia. Without the cohering effects of plot, character, and the like, lyric verse is dependent almost exclusively on language to carry out its fiction. Play, puns and euphony pervade the Song. Song 1:6 offers a paradigm example. The girlfriends (literally, the daughters of Jerusalem, 1:5) are implored not to ‘gaze at’ the girl's black skin that has been ‘gazed’ upon by the sun. The Shulammite explains her exposure to the hot Mediterranean sun as a consequence of her brothers' anger that prompted them to set her as a ‘guard’ in the vineyards. The phrase ‘they were angry with me’ may also be read as ‘they burned against me,’ playing on the scorching look of the sun that burns the skin. And the verse ends by playing on the literal and figurative meanings of ‘vineyard’ in the Song. The vineyard, garden or field is the conventional locale of lovemaking in the Song (and thoroughout ANE [Ancient Near East] love poetry). In the Song, however, the vineyard (or garden) is also used as a figure for the girl herself (especially 4:12--5:1; 6:2). It is the latter on which the final line in 1:6 turns: if she was set to ‘guard’ the family's literal ‘vineyards,’ her own more figurative ‘vineyard’ she has not ‘guarded’--this last bit said, no doubt, as a happy boast, which also suggests that the exclamation in 1:5 ("I am black and beautiful") is in no way demuring.