Dr. Saleem Masoudi, Dr. Abdulsalam Yaghfori, and Dr. Samia Shalaalfor their translation from French into Arabic the book of HaïmBrezis"AnalyseFonctinnelle: Théorie et applications" (In English: Functional Analysis: Theories and Applications). The book accurately and easily discussesthe abstract and applied functional analysis. Functional analysis is one of the main branches of mathematics that both pure and applied mathematics is built upon. The book is one of the main references in its field and an important reference book in many universities in France and French universities around the world. The translation of this book into Arabic is a scientific addition to Arab university students in different levels, taking into consideration the absence of similar accurate and comprehensive books in Arabic.