Bahá'u'lláh wrote many books and letters, and `Abdu'l-Bahá (whose name means "Servant of Glory") also wrote many books and letters which Bahá'ís see as special. Finally, Bahá'u'lláh's great-grandson Shoghi Effendi wrote lots of books and letters which Bahá'ís use to better understand the writings of Bahá'u'lláh and `Abdu'l-Bahá. The most important of these books is the Aqdas.