Sirrul-Khilafah is an Arabic treatise penned by the Promised Messiah^(as)—Hazrat Mirza Ghulam Ahmad of Qadian—and published in July 1894. The book unveils the mystery surrounding Khilafah as the means by which the hidden hand of God dispels the darkness of an era and replaces fear with security for the Ummah. In such trying times, Allah raises a Khalifah and breathes into him the spirit to revive a nation against the impending threat of spiritual death. The book illustrates this through the example of Hazrat Abu Bakr^(ra), who the Promised Messiah^(as) refers to as the second Adam of Islam.

When the darkness of dissension, hypocrisy and rebellion threatened the fledgling Muslim community, Abu Bakr^(ra) rose to the occasion and re-established Muslim unity. A parallel scenario would act out in the Latter Days when the Promised Messiah^(as) would arise as the last Adam for the last age, and would fight the forces of dissension to reunite the Muslim Ummah under one banner.