‘The Dawn-Breakers’ book currently available contains the first half of Nabil’s chronicle – “parts of the manuscript were reviewed and approved, some by Bahá’u’lláh, and others by ‘Abdu’l-Bahá”

His [Nabil] chronicle was begun in 1888, when he had the personal assistance of Mírzá Músá, the brother of Bahá’u’lláh. It was finished in about a year and a half, and parts of the manuscript were reviewed and approved, some by Bahá’u’lláh, and others by ‘Abdu’l-Bahá.

The complete work carries the history of the Movement up to the death of Bahá’u’lláh in 1892.

The first half of this narrative, closing with the expulsion of Bahá’u’lláh from Persia, is contained in the present volume. Its importance is evident. It will be read less for the few stirring passages of action which it contains, or even for its many pictures of heroism and unwavering faith, than for the abiding significance of those events of which it gives so unique a record.

- Shoghi Effendi  (‘Introduction to ‘The Dawn-Breakers’)

The awesome effects of the “onrushing winds of the grace of God” that Bahá’u’llah’s Revelation has brought to the world

“The onrushing winds of the grace of God,” He, in the Súratu’l-Haykal, proclaims, “have passed over all things. Every creature hath been endowed with all the potentialities it can carry. And yet the peoples of the world have denied this grace! Every tree hath been endowed with the choicest fruits, every ocean enriched with the most luminous gems. Man, himself, hath been invested with the gifts of understanding and knowledge. The whole creation hath been made the recipient of the revelation of the All-Merciful, and the earth the repository of things inscrutable to all except God, the Truth, the Knower of things unseen. The time is approaching when every created thing will have cast its burden. Glorified be God Who hath vouchsafed this grace that encompasseth all things, whether seen or unseen!” 

- Shoghi Effendi  (Quoting Bahá’u’lláh in ‘The Unfoldment of World Civilization’)

The growing “capacity” of the “world of being” for the "potentialities" of the revelation of Bahá’u’lláh

“The heights,” Bahá’u’lláh Himself testifies, “which, through the most gracious favor of God, mortal man can attain in this Day are as yet unrevealed to his sight. The world of being hath never had, nor doth it yet possess, the capacity for such a revelation. The day, however, is approaching when the potentialities of so great a favor will, by virtue of His behest, be manifested unto men.” 

- Shoghi Effendi  (Quoting Bahá’u’lláh in ‘The Unfoldment of World Civilization’)

Báhá’u’lláh’s Tablets to “the emperors of the West and the potentates of the East”: - the “diversity of the subjects touched upon”

No less amazing is the diversity of the subjects touched upon in these Tablets.

• The transcendent majesty and unity of an unknowable and unapproachable God is extolled, and the oneness of His Messengers proclaimed and emphasized.
• The uniqueness, the universality and potentialities of the Bahá’í Faith are stressed, and the purpose and character of the Bábí Revelation unfolded.
• The significance of Bahá’u’lláh’s sufferings and banishments is disclosed, and the tribulations rained down upon His Herald and upon His Namesake recognized and lamented.
• His own yearning for the crown of martyrdom, which they both so mysteriously won, is voiced, and the ineffable glories and wonders in store for His own Dispensation foreshadowed.
• Episodes, at once moving and marvelous, at various stages of His ministry, are recounted, and the transitoriness of worldly pomp, fame, riches, and sovereignty, repeatedly and categorically asserted.
• Appeals for the application of the highest principles in human and international relations are forcibly and insistently made, and the abandonment of discreditable practices and conventions, detrimental to the happiness, the growth, the prosperity and the unity of the human race, enjoined.
• Kings are censured, ecclesiastical dignitaries arraigned, ministers and plenipotentiaries condemned, and the identification of His advent with the coming of the Father Himself unequivocally admitted and repeatedly announced.
• The violent downfall of a few of these kings and emperors is prophesied, two of them are definitely challenged, most are warned, all are appealed to and exhorted. 

- Shoghi Effendi  (‘The Promised Day Is Come’)