If you haven't already heard through Twitter, the GateIn Cookbook from Packt Publishing was published early November.
GateIn Cookbook was co-written by Piergiorgio Lucidi, Luca Stancapiano from Sourcesense and myself. GateIn Cookbook provides solutions whether you're planning to develop a new GateIn portal, migrate a portal, or only need to answer a specific query. It is filled with bite-sized recipes for quick and easy problem resolution. From the beginning to the end it will guide you through the process of configuring and securing a portal, managing content and resources, and developing applications as you go.