Pharo is a dynamic object-oriented programming language. Pharo's model and syntax are uniform, simple and expressive. These properties, when added to a powerful and flexible programming environment, regularly attract new developers. Pharo leverages the software building experience to its best. It offers open and object-oriented programming environments and libraries. The book covers a large spectrum of topics ranging from central language aspects to innovative frameworks and libraries. This book contains unique material often presented in a tutorial form with many experiences to carry on. Everybody will learn something reading this book: programmers familiar with Pharo will enjoy the highlights made of some particularly beautiful aspects of Pharo as well as discovering new and powerful frameworks. Deep into Pharo presents internal aspects of Pharo that proved to be important for academic, business and development perspectives.