Application blocks help address the common problems that developers face from one project to the next. Their design encapsulates the Microsoft recommended best practices for .NET applications; developers can add them to .NET applications quickly and easily. For example, the Data Access Application Block provides access to the most frequently used features of ADO.NET, exposing them through easily used classes. In some cases, application blocks also add related functionality not directly supported by the underlying class libraries.

Enterprise Library is a collection of application blocks and services intended for use by developers who build complex, enterprise-level applications. These applications are typically deployed widely and have interdependencies with other application and systems. In addition, they generally have strict security, reliability, and performance requirements.

The goals of Enterprise Library are the following:

• Consistency. All Enterprise Library application blocks feature consistent design patterns and implementation approaches.
• Extensibility. All application blocks include defined extensibility points that allow developers to customize the behavior of the application blocks by adding their own code.
• Ease of use. Enterprise Library offers numerous usability improvements, including a graphical configuration tool, a simpler installation procedure, and clearer and more complete documentation and samples.
• Integration. Enterprise Library application blocks are designed to work well together and are tested to make sure that they do. It is also possible to use the application blocks individually.

This section contains the following topics that will help you to understand this release of Enterprise Library and how you use it alongside earlier versions or migrate your applications to this version. This section includes the following topics:

• About This Release of Enterprise Library
• Target Audience
• System Requirements
• Application Block Dependencies
• Migration and Side-by-Side Execution
• Guidelines for Extending Enterprise Library
• Guidelines for Modifying the Application Blocks
• Related patterns & practices Links
• Copyright and Terms of Use

The remaining sections of this guidance describe the ways that you can use Enterprise Library and the individual application blocks in your applications, how you can extend and modify the blocks, and an API reference. The following are the remaining sections of this guidance:

• Getting Started with Enterprise Library
• Developing Applications with Enterprise Library
• Design of Enterprise Library
• The Caching Application Block
• The Cryptography Application Block
• The Data Access Application Block
• The Exception Handling Application Block
• The Logging Application Block
• The Policy Injection Application Block
• The Security Application Block
• The Unity Application Block
• The Validation Application Block