"A Treatise on the Differential Calculus" is a comprehensive calculus textbook written to guide readers through the core principles of differential calculus in a clear, structured manner. Rather than rushing through formulas, this treatise builds understanding step by step, breaking down complex mathematical ideas into explanations that are easy to follow. Its standout feature is the methodical progression of topics, which allows readers to develop a solid foundation before advancing to more challenging material. For students searching for a reliable calculus reference guide, this book addresses a common problem: many calculus resources assume prior familiarity with advanced notation or skip over foundational reasoning. This treatise instead walks through essential concepts systematically, making it useful for coursework, self-study, or review before exams. Educators can also draw on its structured presentation when preparing lessons or supplementary materials, since the explanations are designed to reinforce conceptual understanding rather than mere memorization of rules. This differential calculus textbook is best suited for students beginning their formal study of calculus, self-learners working independently, and educators seeking a dependable classroom or reference resource. Anyone looking to learn differential calculus with a text that emphasizes clarity and logical progression will find this treatise a practical addition to their mathematics library, offering lasting value as a study companion through multiple stages of calculus education.