Bitter comments about book or collection of books (5)
I believe the answer is:
bible
'collection of books' is the definition.
'bible' can be an answer for 'books' (I have seen 'Holy books ' mean 'bible' so perhaps 'books' could also mean 'bible'). I'm unsure of the 'collection of' bit.
'bitter comments about book' is the wordplay.
'bitter comments' becomes 'bile' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' indicates putting letters inside.
'book' becomes 'b' (abbreviation for book).
'bile' placed around 'b' is 'BIBLE'.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for bible that I've seen before include "Authoritative source" , "Holy Scripture" , "See 12" , "An authoritative text" , "Holy books" .)