source code management

Does Xojo support the ability to have include libraries so I can reuse code? If so, how can I use it?

Thanks for any help you may provide.

that is called “external” module, class, window in the reference manual
http://developer.xojo.com/userguide/sharing-code
http://developer.xojo.com/userguide/advanced-language-features

Thank you. Much appreciated!