The book describes how was to organize the Brazilian and Paulista Natural Gas law service in a comprehensive perspective, as an Energy Centre, named RCGILex, which becomes a comprehensive compilation of the Federal and state level norms, as well as major municipal legal measures impacting (directly or indirectly) in the evolution of the natural gas industry; along with comments from leading natural gas experts, besides the promotion of many events as a way to instigate discussions and analysis on natural gas sector rules in Brazil. Also, the book shows how was to carry out institutional analyze of regulatory frameworks applied to the natural gas sector in Brazil, as well as how was the methodology chosen in order to describe energy centres in some countries and how to get lessons from them.