Shoghi Effendi (1897–1957) succeeded his grandfather, 'Abdu’l-Bahá, as the head of the Bahá’í Faith in 1921. In order to give the Bahá’í Faith organization, Shoghi Effendi established the institutional structure of local and national spiritual assemblies based on principles delineated in 'Abdu’l-Bahá’s Will and Testament and in Bahá’u’lláh’s writings. He translated many of Bahá’u’lláh’s works into English and wrote letters and essays (some 34,000 altogether) defining and clarifying many basic Baha'i teachings. He used the administrative institutions as an instrument for spreading the Bahá’í Faith systematically worldwide. Before his death in 1957, Shoghi Effendi appointed twenty-seven Bahá’ís as “Hands of the Cause of God.” They served as joint custodians of the Bahá’í Faith for five years after his death, until the Universal House of Justice could be elected.

In 1844, Siyyid 'Ali-Muhammad of Shiraz (1819-1850 CE) took the title of the “Báb” (or “Gate”), and claimed to be the promised one expected by Shi’ite Islam as well as prophecies of other world religions, and the Herald of One greater soon to come. In his short six-year ministry he produced over 2,000 works. Because his teachings were considered blasphemy by the Shi'ite clerics, the Báb was executed by firing squad on July 9, 1850. Despite the repeated pogroms against his followers, the movement continued to grow, eventually developing into the Bahá’í Faith.

Bahá’u’lláh (1817–1892) was born in Iran as Mirza Husayn 'Ali and became the most influential of the early followers of the Báb. He acquired the title Bahá’u’lláh (Arabic for "the Glory of God") in 1848. In 1863 he announced a claim to be a messenger of God, the one whose coming was predicted by the Bible, the Qur’an, and by his forerunner, the Báb. Because of his claims, Bahá’u’lláh was repeatedly imprisoned and banished. In his forty-year ministry he produced over over 18,000 unique works, mostly letters and prayers, which defined the basics of his religion. He died in 1892 in Akka, a prison city in Palestine.

A fireside is a common type of Bahá’í meeting, a gathering in a Bahá’í home to discuss the faith. Bahá’ís are encouraged to host such gatherings regularly. Bahá’í communities also sponsor large public firesides in a home or a Bahá’í Center. These events begin with a presentation, followed by questions, discussion, and refreshments.

The Bahá’í year includes nine holy days: the first, ninth and twelfth day of Ridvan (when Bahá’u’lláh declared himself a messenger of God, April 21-May 2); the anniversary of the Báb's declaration that he was the Promised One of Shi’ite Islam (May 23); the anniversary of the birth of Bahá’u’lláh (November 12); the anniversary of the birth of the Báb (October 20); the anniversary of the ascension of Bahá’u’lláh (May 29); the anniversary of the martyrdom of the Báb (July 9); and the feast of Naw-Ruz (New Year, March 21). On these days Bahá’ís should suspend work. The various holy days are celebrated by a program of worship followed by cultural events and refreshments.

The Bahá’í community generally gathers on the first evening of each Bahá’í month, or once every nineteen days. Each Feast has three portions: worship, administrative and socializing. The devotional portion tends to center on two activities: the reading of scripture, especially the writings of the Báb, Bahá’u’lláh, and `Abdu’l-Bahá, and live or recorded music. The administrative portion of a feast focuses on community activities and concerns. All Feasts close with refreshments.

The Feast of Ridvan celebrates the declaration by Baha’u’llah that he was a messenger of God, an event which took place between April 21 and May 2, 1863. Three of the nine Holy Days of the Bahá’í calendar fall within this period: the first, ninth, and twelfth day of the month of Ridvan.

The spiritual assembly is the basic organizational structure of the Bahá’í Faith. Local spiritual assemblies may be formed anywhere that nine or more Bahá’ís live, and national spiritual assemblies are created at the national or regions level when local development is sufficient. Today, there are more than 11,000 local assemblies around the world, and national spiritual assemblies have been elected in 182 countries. Assemblies are elected in a spiritual atmosphere of prayer, where each person silently considers the qualities of an assembly member, prays, and votes his or her conscience. There are no nominations, mention of names, or campaigning in Bahá’í elections.

The Bahá’í Faith first took shape in 1863 when Bahá’u’lláh (1817-1892) declared himself a divine messenger and the messianic figure predicted by the Bab (1819-1850). The religion stresses the oneness of God, the divine origin of all the world’s major religions and their main ethical teachings, the essential harmony of science and religion, the common foundation of all religions, the equality of men and women, and the need to eliminate prejudice of all kinds. The Faith is based on the writings of Bahá’u’lláh, the Báb and `Abdu’l-Bahá, which are considered sacred texts. The Bahá’í Faith is organized by a series of nine-member councils at the local, national and international levels, elected after prayer and meditation without any nominations, campaigning, or prior mention of names. As of 2013, the Bahá’í community worldwide numbers over five million and Bahá’ís reside in more than 200 countries and territories, making the Bahá’í Faith the second-most-widespread religious community, after Christianity.

The Universal House of Justice is the nine-member worldwide governing body of the Bahá’í Faith. It is elected every five years by the members of the National Spiritual Assemblies according to the same principles of spiritual election as are used for local and national spiritual assemblies. The Universal House of Justice is located at the Bahá’í World Center on Mt. Carmel in Haifa, Israel.

Upon the death of Bahá’u’lláh in 1892, his son Abbas Effendi (1844-1921 CE), took the title `Abdu’l-Bahá (“Servant of Bahá’u’lláh”) and assumed the role given him by Bahá’u’lláh as the new head of the Bahá’í community. During his tenure he consolidated the Bahá’í community by opening schools, initiating women's activities, and encouraging all Bahá’ís to observe the Holy Days and feasts. He did much to establish the Bahá’í Faith in Europe and North America. He wrote prolifically, producing over 30,000 letters providing authoritative guidance to the Bahá’ís. Before his death he designated his eldest grandson, Shoghi Effendi Rabbani, as his successor, along with the Universal House of Justice to be elected in the future.