The official Ubuntu book

The free Ubuntu operating system has won the hearts and minds of millions of users worldwide. It combines a strong technical platform, impressive quality, and an enthusiastic global community of users who relentlessly support, document, and test it. The Official Ubuntu Book, Eighth Edition, has been extensively updated with a single goal: to make running today's Ubuntu even more pleasant and productive for you. It's the ideal one-stop knowledge source for Ubuntu novices, those upgrading from older versions or other Linux distributions, and anyone moving toward power-user status. - Publisher.