This first chapter started off with a discussion on the objectives of the book as well as the target readers for the book. The reasons behind choosing each chapter were also briefly mentioned. The bulk of this chapter however dealt with the technology stack we will use in the rest of the book. We started off the technology discussion with Sinatra, the domain specific language used for developing web applications, followed by DataMapper, a popular Ruby object-relational mapping (ORM) library and finally rounding off with Haml, a Ruby-specific templating engine. We rounded off this chapter with a description of the structure of the rest of the chapters. With this, let's start with the first clone chapter.