This book elucidates one of the most significant major issues of Islam, which is the independence of divine legislation, and Islam's fight against innovations and misguided methodologies. It clarified the concept of the steadfastness and comprehensiveness of Islamic Sharia, and addressed the "weakening of legal evidence" with an analytical study of the ideas of various sects. It also examined the issue of the comprehensiveness of Sharia through the study of (generality), (interests), and (analogies), and their impact on the continuation of ijtihad (independent reasoning) and keeping up with new developments. It also highlighted the importance and role of consensus, and discussed in detail the change in fatwa (religious edict) with changing circumstances. It clarified the conditions for acting upon public interest, emphasizing the steadfastness of Islamic Sharia, so that the Islamic society remains firm with the rulings of Sharia, achieving movement around a fixed axis, while following up on new developments and interacting with changes.