23 Years: A Study of the Prophetic Career of Mohammad is a book written by the Iranian author Ali Dashti.

The book contains criticism of the Quran:

The Qur'an contains sentences which are incomplete and not fully intelligible without the aid of commentaries; foreign words, unfamiliar Arabic words, and words used with other than the normal meaning; adjectives and verbs inflected without observance of the concords of gender and number; illogically and un grammatically applied pronouns which sometimes have no referent; and predicates which in rhymed passages are often remote from the subjects. These and other such aberrations in the language have given scope to critics who deny the Qur'an's eloquence.^[1]