Nano Taboada

Grails is an open-source, rapid web application development framework that provides a super-productive full-stack programming model based on the Groovy scripting language and built on top of Spring, Hibernate, and other standard Java frameworks.

Jason Rudolph is an Application Architect at Railinc, where he develops software that helps keep trains moving efficiently throughout North America.

The book can be downloaded for free (registration required), but also you could always purchase the printed copy.