This thesis entitled The Arabic Dialects in Al Outabi's Al Ibana Fil Lugha Al Arabiya (Revelation in Arabic)(After 450 H): A Descriptive and Analytical Study. It deals analytically and descriptively with the dialects mentioned in Al Ibana. It consists of an introduction, preface, six chapters and a conclusion. I. Introduction. II. Preface: It contains five sections: (1) A biography of Al Outabi, (2) The previous studies, (3) Defining "Dialect", (4) Ways of mentioning dialects, (5) terminologies of dialect evaluation. III. Chapter One: The Induction of the Ascribed Dialects in Al Ibana This chapter traces the dialects mentioned by Al Outabi in Al Ibana and divides them according to frequency of mention in the order of those of tribes, of places and territories, of cities and then other dialects. IV. Chapter Two: Dialects of consonants This chapter deals with the dialects related to consonants in accordance with some phonological phenomena such as glottalisation, substitution, assimilation, deletion, doubling and stopping. V. Chapter Three: Dialects of Vowels This chapter presents the dialects of Arabic vowels as well as the dialectic difference in the level of short vowels. The information is dealt with in accordance with the phonological phenomena and in relation to the first and second syllables like vowel suitability, vowel prolonging, doubling, valourisation, leaning, deletion and stopping. VI. Chapter Four: Dialects with Morphological Phenomena 1) The dialects related to the morphological phenomena in nouns and verbs; 2) The dialects of substituting wa and ya as well as the dialects of placement substitution. VII. Chapter Five: Dialects with syntactic phenomena This chapter deals with the dialects in relation to syntax in the order of nouns, verbs and prepositions. VIII. Chapter Six: Dialects with semantic phenomena This chapter talks about the dialects in relation to semantics such as synonymy, homonymy, antonymy, Arabicised borrowings and derivation in relation to Arabic cities and territories. IX. Conclusion: 1) Findings and recommendations; 2) Resources and references.