title_body: How to add external epub to Kobo Desktop?
upvoted_answer: Please note that if you simply need to transfer .epub files to the reader, you can simply connect it to your computer with an USB cable, it will be treated like an external USB storage drive; you can simply copy your books on the reader (maybe on a new sub-directory to keep things clean and neat) and when you disconnect it, it will update the database and recognize your new books. There isn't anything easier than this ;-)
  
  Anyway for a more complete management, I suggest you to try Calibre, it is a superb ebook manager itself with a ton of features; also, it is free and opensource and it is available for Linux systems too, if these are things that are relevant for you.
  
  One of its strengths is the opportunity to add plugins to extend its functionalities. It works perfectly with any ereader device, without the need to add anything, but I suggest to you a couple of plugins that are specifically aimed at Kobo users, that can be useful to have:
  
  
  Kobo Touch Extended Driver: It replaces the standard Kobo device driver shipped with Calibre, its main feature is to optimize the .epub books you are sending to the device with the particular format used by Kobo, called .kepub.epub. Kobo e-readers have two different readers inside (I mean "reader" as a software here), one is used for standard ePub files while the other has some different features and is used for Kepubs. I prefer the last one, but in the end it is a matter of personal preferences, so I suggest you to try both of them and see which format you like the most.
  Kobo Utilities: this is a must-have tool, IMHO. It allow you to perform many operations directly on the device, by manipulating its internal database; it is nothing too complicate, but it could be considered as a tool for advanced users that know what they are doing; I must say that I've never had any kind of problem, but I suggest you to read the warnings from the author. 
  
  
  Please note that you don't have to download these plugins from the MobileRead forum, the easiest way is to install them directly from inside Calibre, where this task can be performed from a nice and handy graphical interface.