New official user manuals for Magento eCommerce are available in Magento Merchant Doc centre
Magento team has published new user guides, both for Magento Enterprise and Magento Community. Good to see that they keep it up to date. Manuals are available in online interactive versions and can be downloaded as PDF.
Here are the links:
http://merch.docs.magento.com/ce/user_guide/Magento_Community_Edition_User_Guide.html Magento Community User Guide (version 1.9.1)
http://merch.docs.magento.com/ee/user_guide/Magento_Enterprise_Edition_User_Guide.html Magento Enterprise User Guide (version 1.14.1)
So if you are using the latest version of Magento for your online store (or plan to use), it is time to update your manuals.