This document provides an overview of Rhodes and cross-platform mobile application development. It discusses key aspects such as using Ruby to build apps that run natively on platforms like iPhone, Android and BlackBerry. It also covers Rhodes-specific topics including the RhoMobile Object Mapper database, synchronization with RhoSync, and a modified version of JQTouch for building views. The document aims to explain what it means for an app to be truly native, differences from Rails, and how threading works in Rhodes applications.