This is the book of the Rhymed Couplets (Mathnawi Mesnevi). It contains the roots of the roots of the roots of the (one true) Religion (of Islam); and treats of the discovery of the mysteries of reunion and sure knowledge. It is the Grand Jurisprudence of God the most glorious Law of the Deity the most manifest Evidence of the Divine Being. The refulgence thereof "is like that of a lantern in which is a lamp" that scatters beams more bright than the morn. It is the paradise of the heart with springs and foliage. One of those springs is "the fount named Salsabil" by the brethren of this religious order (of mystical devotees known as the Mevlevi or Dancing Dervishes); but by saints and the miraculously endowed it is called "the Good Station" and "the Best Resting-place." The just shall eat and drink therein and the righteous shall rejoice and be glad thereof. 
This book contains a translation of the great poem collection "The Mesnevi of Rumi" and some anecdotes' explanations as a separate part.