Alright; perhaps I am missing something very obvious, but here's my problem:
A while back Calibre didn't send books to iBooks on my Macbook pro OSX 10.7.5. After several in-and re-installing the iOs-reader plugin I left it; I dragged my books to iTunes to synchronize with iBooks.
Also I installed Marvin and connected Calibre to it. That worked.
Now I've an iPad air iOs 7.0.4. and Calibre(1.15) sends books to iTunes, but iTunes doesn't synchronize with iBooks. That's why I drag my books in Dropbox and use the option 'open in iBooks'. That works.
Calibre doesn't see Marvin any more though. When I open Marvin on the iPad, the 'cloud' icon doesn't appear. (It does for Dropbox).
Several times I de-and re-installed both the iOs reader application plugin and the Marvin XD plug in as advised in "Marvin for iOs", with the iDevice de-connected and connected as advised and Calibre started and restarted.
I would like to have at least one reader application that works directly with Calibre on my iPad air.
What am I doing wrong? I would like to use either iBooks or Marvin with Calibre, or both......
I would appreciate some thoughts on this puzzle.