Like the English translation of the Quran, this book is a gateway for the native English-speaker to learn about a great world religion: The Bahá'i Faith.
As a Latter-day Saint, I was struck by the similarities in temporal mission (early - mid 19th century), syncretic theological orientation to the unity of all truth regardless of origin, health code, and emphasis on the pure teachings of Jesus Christ between our two faiths. I have tremendous respect for the Bahá'i Faith and its faithful adherents, and especially admire how they eschew evil-speaking of each other, or anyone for that matter. This is a real strength of their faith, and one I hope to learn well from them.
My understanding of the Bahá'i Faith is still elementary, but I do wonder to what extent Baháʼu'lláh equivocated himself with God, a claim that may have strengthened over time as the faith spread globally. It's not a highly structured or organized faith, so may see doctrinal creep. For example, Esslemont (the author of this book), says an interesting thing on pg. 52: "At other times . . . Bahá'u'lláh speaks 'from the station of Deity.' In these utterances His human personality is so completely subservient that it is left out of account altogether." This signifies that he was a human who at times acted as a mouthpiece of God, as have and do other prophets of the Lord.
The remarkable spread of the faith through at least the English-speaking world seems to have happened in three spurts: 1. The Victorian fascination with the Oriental, 2. The global hunger for peace and disillusionment during and after the Great World Wars, and 3. The countercultural movements of the 60s and 70s, which were also in reaction to the military-industrial complex of the West.
The Bahá'i Faith contains tremendous truth and beauty, and is well worth studying and living.