The 15th of Av is undoubtedly the most mysterious day of the Jewish calendar. A search of the Shulchan Aruch ("Code of Jewish Law") reveals no observances or customs for this date, except for the instruction that beginning on the 15th of Av, one should increase one’s study of Torah, since at this time of the year the nights begin to grow longer and "the night was created for study." And the Talmud tells us that many years ago the "daughters of Jerusalem would go dance in the vineyards" on the 15th of Av, and "whoever did not have a wife would go there" to find himself a bride.
And this is the day which the Talmud considers the greatest festival of the year, with Yom Kippur(!) a close second!
Indeed, the 15th of Av cannot but be a mystery. As the "full moon" of the tragic month of Av, it is the festival of the Future Redemption, and thus a day whose essence, by definition, is unknowable to our unredeemed selves.
Yet also the unknowable is ours to seek and explore, as we shall in two essays, based on the Lubavitcher Rebbe's writings and talks, presented here. The Day of the Breaking of the Ax approaches the mystery of Av 15 by examining a number of events which occurred on this day. The Dancing Maidens of Jerusalem sees in the Talmud's account of their match-seeking dance a model for the various dimensions of our relationship with G‑d: