Two marks found in each novel (4)
I believe the answer is:
emma
'novel' is the definition.
(I've seen this before)
'two marks found in each' is the wordplay.
'two' indicates the doubling of some letters.
'marks' becomes 'm' (former German currency).
'found in' means one lot of letters goes inside another.
'each' becomes 'ea'.
'm' doubled is 'mm'.
'mm' going into 'ea' is 'EMMA'.
(Other definitions for emma that I've seen before include "Retired chief in Ian Fleming" , "Miss Woodhouse?" , "Ack -, a term for a.m." , "Lady - Hamilton, Nelson-s mistress" , "heroine of novel" .)