This site is where you can find the official documentation developed and maintained by the Ubuntu Documentation Project.
This page contains documentation for Ubuntu 6.06 LTS (Dapper Drake). Find more documentation by clicking on the tabs at the top of this page.
Find out more about Ubuntu and Kubuntu from the following documents:
Ubuntu - About Ubuntu
Kubuntu - About Kubuntu
If you can't find what you are looking for here, try the excellent source of community contributed documentation.