Apologetics is the branch of theology which seeks to defend a religion's tenets through reasoned argument.Bahá'ís generally believe that the proof of the truth of the religion can be found through independent investigation. In Bahá'í thought, the validity of the various Manifestations of God, prophets in the Bahá'í writings that include Jesus, Muhammad, Gautama Buddha and Bahá'u'lláh among others, is reasoned through the power of the word of God, the revelation of divine verses, the characteristics of the prophets, the fulfillment of prophecy, and the teachings brought by the prophet; miracles, however, are not regarded as proof of divinity.

Many apologetic books have been written in response to attacks on the religion's history and teachings. The religion's founders themselves wrote several books in response to such questioning presenting proofs of their religion, among them are the Báb's Seven Proofs and Bahá'u'lláh's Kitáb-i-Íqán. Later Bahá'í authors wrote prominent apologetic texts, such as Mírzá Abu'l-Fadl's The Brilliant Proof and Udo Schaefer et al.'s Making the Crooked Straight; and today there is an extensive library of such resources.

The Bahá'í Faith ( /bəˈhaɪ/) is a monotheistic religion founded by Bahá'u'lláh in 19th-century Persia, emphasizing the spiritual unity of all humankind. There are an estimated five to six million Bahá'ís around the world in more than 200 countries and territories.

In the Bahá'í Faith, religious history is seen to have unfolded through a series of divine messengers, each of whom established a religion that was suited to the needs of the time and the capacity of the people. These messengers have included Abraham, Moses, Jesus, and Muhammad - as well as figures from extra-Abrahamic traditions such as Zoroaster, Krishna, and the Buddha. For Baha'is, the most recent messengers are the Báb and Bahá'u'lláh. In Bahá'í belief, each consecutive messenger prophesied of messengers to follow, and Bahá'u'lláh's life and teachings fulfilled the end-time promises of previous scriptures. Humanity is understood to be in a process of collective evolution, and the need of the present time is for the gradual establishment of peace, justice and unity on a global scale.