The World Order of Bahá'u'lláh is a collection of letters and messages from Shoghi Effendi, head of the Bahá'í Faith during the period, first published in 1938.
While the letters to the American Bahá'í community from Shoghi Effendi between 1922 and 1929, published under the title of Bahá'í Administration, explained and encouraged the development of the administrative institutions created by Bahá'u'lláh and further elaborated by `Abdu'l-Bahá, the letters published in The World Order of Bahá'u'lláh have a different aim and a far larger scope. These later communications unfold a clear vision of the relation between the Bahá'í community and the entire process of social evolution under the dispensation of Bahá'u'lláh. The distinction between the Bahá'í community and the sects and congregations of former religions had been made apparent, but the present volume establishes the Baha'i Administrative Order as the nucleus and pattern of the world civilization emerging.
In the introduction, Horace Holley, a notable Hand of the Cause wrote:
In the section entitled "Unity in Diversity", Shoghi Effendi described underlying principles of the Baha'i Faith,