Book excerpt: The history of Islamic thought is marked by a continuous tradition of internal revitalisation and reform embedded in the principles of islah, and tajdid. The ultimate purpose has been to bring existing realities and social change in line with the transcendent and universal standard of the Qur’an and Sunnah through a process of restoration and reform. The tradition of islah-tajdid has thus consistently challenged the Muslim status quo and prompted fresh interpretation of the Qur’an and Sunnah, understood and implemented through the methodologies of interpretation and ijtihad, as well as the rejection of unwarranted accretions to the original messages of Islam. The basic theme of the paper is that civilisational renewal is an integral part of Islamic thought. The paper looks into the meaning, definition and origins of tajdid and islah and their relationship with ijtihad, and how these have been manifested in the writings and contributions of the thought leaders of Islam throughout its history. It also develops tajdid-related formulas and guidelines that should lead the efforts of contemporary Muslims in forging the objectives of inter-civilisational harmony and their cooperation for the common good.