|
If you want the books to open in Calibre's viewer when you open them from within Calibre itself, check preferences->behaviour. There's a list of formats to be opened in the ebook viewer on the lower right hand side.
If you want to open ePubs in the Calibre viewer when you open them in your file manager, you'll need to associate the files to open with the viewer. I don't know how to do that on OSX.
|