This document introduces Glimmer DSL for SWT, a Ruby GUI framework that allows building native graphical user interfaces in Ruby. It discusses the motivation for building native GUIs, provides examples of sample apps built with Glimmer, and outlines the basics of the GUI DSL syntax. Key aspects covered include widgets, properties, listeners, operations, software architecture patterns like MVC and MVP, data binding, custom components, drag and drop, and scaffolding tools. It also mentions the ability to package apps into various native executable formats like DMG, PKG, EXE, MSI, DEB, and RPM for different platforms.