The holy book of Islam is quran.

The Quran, often spelled as "Quran" or "Koran," is the holy book of Islam. It is considered by Muslims to be the literal word of God as revealed to the Prophet Muhammad through the Angel Gabriel over a period of approximately 23 years. The Quran is written in Arabic and is divided into chapters called "Surahs," which are further divided into verses called "Ayahs."

The Quran covers a wide range of topics, including theology, morality, guidance for personal conduct, legal principles, and stories of previous prophets. It emphasizes monotheism, the worship of one God (Allah), and provides guidance on how Muslims should lead their lives in accordance with Islamic principles.

The Quran is highly revered in Islam and is recited, memorized, and studied by Muslims around the world. It serves as the primary source of religious and moral guidance for Muslims and is recited in daily prayers. It is also studied for its linguistic and literary excellence.

The Quran has had a profound influence on Islamic culture, art, science, and philosophy throughout history and continues to be a central religious and spiritual text for over a billion Muslims worldwide.