This book is a study on the origin and development of the Magadhi Language which has long been a desideratum. Magadhi has been discussed historically in this book. The present text is divided into ten chapters excluding the introduction. In the Introduction an endeavour has been made to focus on the problem of the research. In phonology, divided into four chapters, some phonological problems of Magadhi and their evolutions have been discussed historically. In morphology, a systematic analysis of some problems of the parts of speech has been done historically. Chapter ten is on the conclusion of the study. In the appendix, it has been analysed, perhaps, for the first time, the grammatical texts of Magadhi as given by Raghavabhatta in his commentary on the sixth act of the Abhijnana – Sakuntalam. This text is very interesting from the point of view of Prakrit studies. Raghavabhatta has quoted some sutras which are also interesting in a sense that he has consulted or quoted some Prakrit texts which are not available today.