The Holy Qur'an.

The Quran literally meaning "the recitation"; is the central religious text of Islam, which Muslims believe to be a revelation from God (Allah).It is widely regarded as the finest piece of literature in the Arabic language. Quranic chapters are called suras and verses, ayahs. Muslims believe the Quran was verbally revealed by God to Muhammad through the angel Gabriel (Jibril), gradually over a period of approximately 23 years, beginning on 22 December 609 CE, when Muhammad was 40, and concluding in 632, the year of his death. Muslims regard the Quran as the most important miracle of Muhammad, a proof of his prophethood, and the culmination of a series of divine messages that started with the messages revealed to Adam and ended with Muhammad. English translation also available on kindle.