This extensive 904-page academic study by Dr. Al-Sayed Ezzat Abdel Rahman, published in 2019 with an artistic cover, offers a deep dive into the science of hadith criticism. The book meticulously collects and analyzes rare terms and specialized idioms used by prominent Imams in the field of Al-Jarh wa'l-Ta'dil (criticism and validation of narrators). It serves as an essential reference for researchers and students, clarifying the precise meanings and contexts of this nuanced terminology, thereby preserving the integrity of hadith studies. This work is a valuable contribution to understanding the methodologies of early Islamic scholars.