Muhammad summarized Chapter Ya-Sin with the following noble hadith: “Everything has a heart. The heart of the Quran is Chapter Ya-Sin.” If we think of this universe as an embodiment of the Quran’s meaning, the perfect human beings (al-Insan al-Kamil) described in Chapter Ya-Sin are the heart of this body. As they assume the character traits of the Prophet, they give life to the dead bodies with these character traits. “O Humankind” is an elaborate commentary on the Chapter Ya-Sin, the heart of the Quran, about the inner meanings of each of its verses. Compiled by Cemalnur Sargut, the book is a reference that draws on various tafsir works and the commentaries of the perfect human beings. The great Quran commentary tradition shows us how Muslims have understood their religion over time. The tradition is found here in a selection ranging over ten centuries of commentary on chapter Ya Sin, known as “the heart of the Quran.”