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Introduction
============

**TYPO3** is a powerful and mature content management system containing many features and a large degree of flexibility.

**Extbase** is a PHP-based framework which supports developers in creating clean and easily maintainable TYPO3 extensions.
The template engine Fluid makes sure that the user interface of the extension can easily be created individually.

Extbase ensures a clear separation between different concerns, which makes maintenance a lot more simple thanks to
modular code. Because of this modular design, the development time and associated costs are reduced for initial
development and for adjustments. Extbase also lessens the burden on the developer when it comes to security-relevant
and repetitive tasks: for example the validation of arguments, the persistence of data, and access to TypoScript and
FlexForm settings. Developers can therefore focus on solving the problems of their clients much more efficiently.

Using Extbase needs a basic understanding of concepts like domain driven design, whilst planning and modeling the
extension thoroughly before implementation. In return, the source code of the extension becomes a lot more readable,
more flexible and more extensible.

Target Audience
===============

This book is for TYPO3 extension developers who have a basic
understanding of PHP programming and experience working with
and administering TYPO3. The book gives a compact introduction
to the Extbase framework and to the Fluid template engine.

Read more about the target audience and how this manual is
structured in :ref:`about`.