One of the important teachings of the Quran, which is believed to play a prominent and comprehensive role in human beings’ guidance and prosperity, is Ismah (incorruptible innocence) of the Ahl al-Bayt (As), as expressed in the verse of purification. The doubts raised by some opponents have caused the misunderstanding of the provisions of the verse and raised some questions. In a preface and six chapters of the book, documented responses to 55 questions are provided and it is explained how the verse indicates the Prophet (PBUH) and Ahl al-Bayt’s (AS) incorruptible innocence.