The scientific content included in this book is the result of five years of the author's research work in the field of theoretical nuclear physics. The book is very useful to researchers and research students who are searching for a postgraduate book which enables them to understand and carry out research papers in the field of theoretical nuclear physics in general and especially, nuclear deformations. The author included in this book the contents of her recent five published papers on this topic. It is very recommended that the reader has a good background in quantum mechanics and theoretical nuclear physics.