(Ruhiyyih Khanum, The Guardian of the Baha'i Faith, p. 93)Remembering the scanty pages of the New Testament, the reputed words of Buddha, and the mere handful of sayings of some other Divine luminaries, which nevertheless have transfigured for centuries the lives of millions of men, the Gleanings alone seems to provide a source of guidance and inspiration sufficient for the spiritual Dispensation of any Prophet. The most treasured tribute to this book was that of Queen Marie of Rumania who told Martha Root: "even doubters would find a powerful strength in it, if they would read it alone, and would give their souls time to expand." To Shoghi Effendi himself the Queen wrote, in January 1936, after receiving from him a copy, "May I send you my most grateful thanks for the wonderful book, every word of which is precious to me, and doubly so in this time of anxiety and unrest."
For an inspiring and informative review of its contents, please see the transcript of a talk given by Mr. Ali Nakhjavani, a member of the House of Justice. A copy is posted at Baha’i Talks.