One of the tools suggested by LuLu to create an Epub eBook was eCub (also for MobiPocket books, which are similar to the Amazon kindle format). I was able to install eCub on my Ubuntu netbook and run it. I also tried the more sophisticated Calibre tool but was unable to install it (and caused problems with my Linux configuration in the process).
I like the eCub approach which is that while it has a graphical user interface, it is a simple batch program working on a directory of files underneath. You place the content you want converted to ePub in a folder and then run eCub, which creates the ePub file. You can't preview or edit the document with eCub, you have to use other programs to do that, all it does is take the files you provide and package them up.
On my first attempt I created a book which has a cover and all the content, but the menu is not correct. However, this is good progress for a few minutes work (after hours of working out why Calibre did not run and what happened to my software configuration).