This document discusses the history of hadith compilation in Islam. It explains that hadith are the sayings and actions of the Prophet Muhammad and were initially orally transmitted. It then outlines the major periods of hadith compilation: during the Prophet's lifetime, the time of the companions, followers of companions, and followers of followers. The most authentic books of hadith, the six major Sunni hadith collections, were compiled during the last period. Precautions taken to ensure authenticity included verifying complete and unbroken chains of narrators and checking the text did not contradict Islam or other sources.