Description from the publisher:

Abu Hamid al Ghazali, one of the most famous intellectuals in the history of Islam, developed a definition of Unbelief (kufr) to serve as the basis for determining who, in theological terms, should be considered a Muslim and who should not. Jackson's annotated translation is preceded by an introduction that reconstructs the historical and theoretical context of the Faysal and discusses its relevance for contemporary thought and practice.

This is particularly relevant to the contemporary Muslim theological scene, given the on-going controversy between Revivalist groups, Rationalist and Traditionalist, as to what is the true interpretation of religion and what constitutes a grave deviation from it.