"Essay in Aid of Consonant Grammar" is a fundamental philosophical and religious work of the outstanding English writer and theologian John Henry Newman. In this book, the author examines the issue of faith and beliefs, as well as the process of an individual's awareness of his faith. Newman explores the nuances of rational arguments in support of faith, expresses ideas about the nature of human cognition, and expresses doubts about the possibility of fully understanding faith using only rational methods. This book not only forces the reader to think more deeply about his own beliefs, but also opens new horizons in the field of philosophy and theology.