Paolo Perrotta is a traveling coach and a software mentor. He wrote "Metaprogramming Ruby", widely praised as one of the essential books on Ruby. He has hundreds of articles, conference speeches and training deliveries under his belt, and he developed software in domains ranging from automotive to healthcare, large-scale web sites, and computer games. He's also been a member of the team that developed Hibernate, one the world's most popular Object-Relational Mappers.