John Ebenezer Esslemont M.B., Ch.B. (1874 – 1925), from Scotland, was a prominent British adherent of the Baháʼí Faith. Shoghi Effendi, Guardian of the Baháʼí Faith, posthumously named Esslemont a Hand of the Cause of God, one of the Disciples of ʻAbdu'l-Bahá (Effendi's predecessor), and one of the United Kingdom's three luminaries of the Baháʼí Faith.^[1] He was the author of one of the foremost introductory texts on the Baháʼí Faith (Baháʼu'lláh and the New Era) and worked as a translator of Baháʼí texts near the end of his life. In addition to his work for the Baháʼí Faith, Esslemont was an accomplished physician, as well as a linguist, proficient in English, French, Spanish, German, Esperanto, and later Persian and Arabic. Dr. Esslemont died of tuberculosis in Palestine in 1925.

In 1916 Esslemont began working on a book which was to become Baháʼu'lláh and the New Era, perhaps the foremost introductory volume on the Baháʼí Faith which was eventually published in 1923, and has since been translated into dozens of languages.^[2][6]

Due to the demands of his professional life, he had only completed half the book by May 1918, and when in the latter part of that year Abdu'l-Baha was made aware of Esslemont's book project, he requested a copy for his review, Esslemont forwarding the nine chapters he had completed in January 1919. His plan had been to visit Haifa in July 1919, Abdu'l-Baha requesting that he take the completed manuscript with him; however, since Esslemont hadn't completed the book he postponed his visit for a few months, arriving in Haifa in early November and staying until 23 January 1920. During this time, Abdu'l-Baha reviewed the book and spoke with Esslemont about suggestions for its improvement. As a result of having direct access to Abdu'l-Baha, Esslemont was able to collect a considerable amount of new information about the history and teachings of the Baháʼí Faith. He returned to England to revise the book, which he completed in June 1920. The work was then translated into Persian and forwarded to Abdu'l-Baha for final review. Because Abdu'l-Baha died in 1921 before reviewing the work in its entirety, the remainder was reviewed by Shoghi Effendi. The first edition of Baháʼu'lláh and the New Era was published in September 1923 and the American edition was published in October 1924. The book is still in print, though it has gone through many updates and revisions. Baháʼu'lláh and the New Era has been translated into 60 languages and is one of the most widely distributed books on the Baháʼí Faith in the world.

Esslemont also performed the first review of the worldwide progress of the Baháʼí religion in 1919. While unpublished it was identified and reviewed by recent scholars noting it was intended to be a chapter in the book.^[7] In 1920 a review of prayer in the Baháʼí Faith, especially the Long Obligatory Prayer as then translated, was published by Esslemont.^[8] Later an expanded version would be a chapter of Baháʼu'lláh and the New Era.

More than sixty years later in the 1980s it remained in the top ten of cited Baháʼí books^[9] and of the ten most numerous books on Baháʼí topics found in libraries in 2008 around the world the second highest is Baha'u'llah and the New Era.^[10]

Early editions contained several passages that could not be authenticated, or needed corrections. These have been reviewed and updated, under the authority of Baháʼí institutions, in subsequent editions.^[11] This practice has been pointed out by critics.^[12] Baháʼí institutions have written that it is an integral part of maintaining the integrity of the texts and correcting misunderstandings from the era in which it was written.^[13][14][15]

Sometime during his early college years, John Esslemont contracted tuberculosis. As a result, he focused much of his career on the care and treatment of tuberculosis patients. He actively sought out new treatments and techniques to fight the disease, while personally moving to climates that he believed would be more hospitable to his health than his native Scotland. Although the progress of Esslemont's own case was slow, there were no medications available to cure Tuberculosis during his lifetime. After suffering bouts of illness of increasing frequency and duration over nearly three decades, Esslemont died of complications from the disease on 22 November 1925. He is buried in the Baháʼí cemetery at the foot of Mount Carmel in Haifa, Israel.^[16][17]

Shoghi Effendi posthumously designated Esslemont as the first of the Hands of the Cause he appointed in 1951, as well as one of the Disciples of ʻAbdu'l-Bahá.^[1] In 1955, Esslemont was described by Shoghi Effendi as one of the "three luminaries of the Irish, English and Scottish Baháʼí communities."^[18]

Assisted in the translation of the Hidden Words into Esperanto, 1916

What is a Baháʼí: pamphlet published in 1919

British edition of Baháʼu'lláh and the New Era: published in 1923

Baháʼu'lláh and His Message, pamphlet published in 1924

American edition of Baháʼu'lláh and the New Era: published in 1924

Assisted in the translation of the Tablet of Ahmad into English, 1924

Assisted in the translation of Nabil's Narrative into English, 1924

Assisted in the translation of the Hidden Words into English, 1925

• Esslemont, John E. (1980) [Composed 1923]. Baháʼu'lláh and the New Era (5th ed.). Wilmette, Illinois, USA: Baháʼí Publishing Trust. ISBN 0-87743-160-4.
• Effendi, Shoghi (1944). God Passes By. Wilmette, Illinois, USA: Baháʼí Publishing Trust. ISBN 0-87743-020-9.
• Harper, Barron (1997). Lights of Fortitude (Paperback ed.). Oxford, UK: George Ronald. ISBN 0-85398-413-1.