It is the last of the four books by Hitjo Garst about the first 120 years of the Bahá’í Faith and is about Shoghi Effendi, the Guardian of the Faith. His life is inextricably linked to the first forty years of the Formative Age and the building of the Administrative Order, which began in 1921. The Formative Age of the Faith was preceded by the Heroic Age, which began in 1844, in Iran, with the proclamation of the Báb, the Herald of Bahá’u’lláh.

The life of the Báb and His heroic followers is described in the book, The Herald and His Heroes. The book, From Mountain to Mountain, contains forty stories about the life of Bahá’u’lláh, the Founder of the Bahá’í Faith. The Most Mighty Branch, the third book in this series, is about the life and ministry of ‘Abdu’l-Bahá, the son of Bahá’u’lláh. Bahá’u’lláh appointed His Son as the interpreter of His Writings. After Bahá’u’lláh’s Ascension, the unity of His Faith was preserved through ‘Abdu’l-Bahá, just as now and into the future, unity will be preserved through the Administrative Order.