There are two fanatical attitudes that develop in Islamic society, namely fanatics within a school and anti-school fanatics. Attitudes and conditions like this have led to disputes and divisions within the body of the Muslims. In fact, not infrequently differences in furu' (branches) issues can trigger fights and bloodshed among fellow Muslims. It is at this point that the issue of schools of thought in Islamic law becomes important for further investigation. The history of the emergence of schools of fiqh occurred in five periods: The growth period (0-1 H century), namely during the time of the Prophet, during the companions and during the tabiin period. The formation period (2-3 H centuries) was the Imam Abu Hanifah School, the Imam Malik School, the Imam Syafii School, the Imam Ahmad School and other schools. The golden period (3-9 H century). Decline period (10th – 13th century H). And the period of revival (14th Century Present). It turns out that practicing madzhab for other than absolute mujtahid is obligatory according to ushul fiqh scholars. And inviting people to leave the schools of thought on the grounds of returning to the Al-Qur'an and al-Sunnah is a futile effort. Schools should be understood as a scientific discipline (manhaj) for us to understand the Qur'an and al-Sunnah. Therefore, the existence of a school of thought in the contemporary era is still needed to harmonize the factual truths of the Qur'an and as-Sunnah.