ROOT provides different types of documentation:

• The Reference Guide, which is generated by doxygen provides an up-to-date full code documentation. This is mainly for software developers of ROOT and using ROOT to build the applications.
• A general Users Guide is provided for a more in depth explanation of concepts and functionality available in the ROOT system.
• A number of topical User Guides and Manuals for various components of the system.
• A rich set of ROOT tutorials and code examples are offered to developers to exercise specific functionality.
• A rich set of HowTo's is also present to discuss issues commonly faced by ROOT users.