Welcome to the Nucleus CMS WiKi. Here you can find a lot of ongoing documentation for the Nucleus CMS project. It's also one of the best documented resources for plugins, which extend the functionality of the Nucleus CMS core.
Nucleus CMS is a flexible and easy to install content management system, aka blog software. It helps you to publish a website and lets writers do what they are best at: writing items or articles, without having to worry about formatting and markup.