Problem turning back cover on classic novel (7)
I believe the answer is:
dilemma
'problem' is the definition.
(a dilemma is a problem)
'turning back cover on classic novel' is the wordplay.
'turning back' says the letters should be written backwards.
'cover' becomes 'lid' (lid is a kind of cover).
'on' says to put letters next to each other.
'classic novel' becomes 'Emma' (Jane Austen novel).
'lid' written backwards gives 'dil'.
'dil'+'emma'='DILEMMA'
(Other definitions for dilemma that I've seen before include "I'm lamed - it's a puzzle" , "23 [SPOT]" , "Difficult choice; quandary" , "Awkward situation" , "The choice between courses of action, all equally undesirable" .)