This document provides an overview of Apache DeltaSpike, an open source CDI extension library. It discusses DeltaSpike's history and goals of being portable, reusable, and collecting best practices. Key features covered include core CDI capabilities like scopes, testing support, JSF integration for navigation and scopes, and additional modules. The document demonstrates examples and advantages of using DeltaSpike for testing CDI applications and customizing CDI metadata. It aims to close gaps in the CDI specification and provide a solid base for other extensions.