Will and Testament of 'Abdu'l-Baha - by 'Abdu'l-Baha

…the Will and Testament of 'Abdu'l-Bahá, that Charter of Bahá'u'lláh's New World Order, the offspring resulting from the mystic intercourse between Him Who is the Source of the Law of God and the mind of the One Who is the vehicle and interpreter of that Law. (Shoghi Effendi, God Passes By, p. xv)

The Charter which called into being, outlined the features and set in motion the processes of, this Administrative Order is none other than the Will and Testament of 'Abdu'l-Bahá, His greatest legacy to posterity, the brightest emanation of His mind and the mightiest instrument forged to insure the continuity of the three ages which constitute the component parts of His Father's Dispensation. (Shoghi Effendi, God Passes By)

… a document which confirms, supplements, and correlates the provisions of the Aqdas --
(Shoghi Effendi, The World Order of Baha'u'llah, p. 19)

The Priceless Pearl - by Hand of the Cause Ruhiyyih Khanum

The Priceless Pearl, although biographical in treatment, is what the author prefers to call an appraisal of the life and work of this distinguished, unique and far-visioned man, believing that we stand too near to such a towering figure to assemble, at so early a date, a more detailed record of his achievements.

The panorama of his life, so filled with sorrow and drama, victory and crisis, stretches through the pages of this book in a memorable and moving tale of historic events, ably portrayed by the pen of one who was not only a Baha'i from birth, but honoured by becoming the wife of the Guardian or her Faith, who served him tirelessly as his personal secretary, who was appointed by him a Hand of the Cause of God and who he stated had been his "shield" during difficult days of his life.

Born Mary Sutherland Maxwell the author grew up in Montreal, Canada; since the passing of her illustrious husband in 1957 she has travelled all over the world, giving public lectures and devoting particular attention to villagers and tribal peoples whom she has made a special point of visiting in Asia, Africa and throughout Latin America.

Her previous book Prescription for Living has been widely read and translated into a number of languages.
(From the back cover of the book)

God Passes By – written by Shoghi Effendi

God Passes By , the most brilliant and wondrous tale of a century that has ever been told, is truly a "Mother" of future histories, a book wherein every word counts, every sentence burgeons with thought, every thought leads the way to a field of its own. Packed with salient facts it has the range and precision of snowflake crystals, each design perfect in itself, each theme brilliant in outline, coordinated, balanced, self-contained, a matrix for those who follow on and study, evaluate and elaborate the Message and Order of Bahá'u'lláh. It was one of the most concentrated and stupendous achievements of Shoghi Effendi's life, the only true book we have from his pen - because all his other communications were, no doubt due to his profound modesty and humility, in the nature of letters addressed to a specific community or section of the Bahá'í world. ((Ruhiyyih Khanum, 'The Priceless Pearl')

• … God Passes By is a flaming narrative. The character and qualities of the innumerable personages in it spring from the personages themselves and not from the author's fantasy. Like a precious and veritable gift from God, Shoghi Effendi's writing is an infinite, passionate cry from his innermost noble soul: the need to relate with great force and vehemence, without pause or rest, the greatest epic of the millennium. One can well sense that the underlying element of urgency is motivated by the inner impelling need to proclaim it, without delay, to all mankind. 
(Ugo Giachery, 'Shoghi Effendi - Recollections')