Omar Suleiman’s book “40 on Justice: The Prophetic Voice on Social Reform” compiles forty hadiths (proverbs of the Prophet Muhammad) that are concerned with social fairness and reform. Suleiman offers comments and analysis on each hadith, highlighting its applicability to current themes of injustice, oppression, and social unrest by drawing on his extensive understanding of Islamic theology and history. Suleiman highlights the Prophet’s teachings on compassion, equity, and group responsibility through his investigation, and he exhorts readers to incorporate these principles into their own lives and communities. Both Muslims and non-Muslim readers who want to learn more about Islam’s social justice principles should read the book.