The Arabic language is considered one of the oldest Semitic languages, rich and profound, serving as a window into a culture and civilization with roots extending back thousands of years. It carries within it a storied history, a literary and intellectual heritage, and keys to understanding the values and beliefs that shape Arab identity. At the heart of this magnificent language lies the field of Morphology (علم الصرف) one of the most important branches of Arabic, which focuses on the study of word forms and their variations. It enables us to understand how words are constructed and formed from their roots, as well as how they are inflected according to different contexts. This field encompasses the rules that dictate how words change in various cases, their patterns, and forms, reflecting the richness of the language and the diversity of its expressions. Morphology represents the foundational structure upon which Arabic sentences are built, contributing to the clarification of meanings and the extraction of implications from different contexts. Through the study of morphology, we gain a deeper understanding of the relationships between words and how they affect meaning, thereby enhancing our capacity for literary and intellectual expression. Substitution (الإبدال) and alteration (الإعلال) are among the most prominent issues of morphology addressed by Ibn Kamal Pasha in his book Al-Falah Sharh al-Marah, which is a detailed commentary on Marah al-Arwah fi al-Sarf by Husam al-Din Ahmad ibn Ali ibn Mas'ud, a distinguished scholar in the field of morphology. This research focuses on the morphological analysis of substitution and alteration as presented in Al-Falah, highlighting Ibn Kamal Pasha's methodology in explaining these morphological issues. The significance of the title lies in its focus on one of the deeper aspects of morphology, through a thorough explanation of the concept of substitution, which deals with changes occurring in letters, and the concept of alteration, which addresses the phonetic changes occurring among letters in words. Both are considered central issues in the field of morphology. The problem of this research arises from the desire to understand how Ibn Kamal Pasha presented fundamental morphological concepts, particularly concerning substitution and alteration, and the methodology he employed in explaining and simplifying these concepts for students. As the researcher delves into Al-Falah, questions arise: How did Ibn Kamal address the morphological issues related to substitution and alteration? What views and interpretations did he present in this context compared to those of scholars who preceded or followed him? Answering these questions requires a meticulous analysis of the book's content and a dissection of the concepts presented within. How did Ibn Kamal manage to integrate traditional theories with new insights, and how did this impact students' comprehension of complex morphological issues? Through these inquiries, the research aims to provide a comprehensive perspective that deepens the understanding of the morphological approach adopted by Ibn Kamal Pasha, distinguishing it from the opinions of other scholars. In this work, we relied on a descriptive-analytical methodology, initiating the study with two sections: the first introduces the author and the book, while the second is divided into two topics, one focusing on substitution in its various forms, and the other on alteration and its types. The researcher faced several practical and academic challenges: practically, the difficulty of dividing time between motherhood and research, and academically, the challenge of balancing precise morphological analysis with linking those analyses to the texts available in Al-Falah, which required significant effort due to the complexity of the morphological issues addressed in the book.