A book just for you (6)
I believe the answer is:
reader
I believe this is a double definition.
'a book' is the first definition.
(reader is a kind of book)
'for you' is the second definition.
(I've seen this before)
'just' acts as a link.
(Other definitions for reader that I've seen before include "Interpreter of what is written" , "(User of) standard textbook" , "Text book -- red ear (anag)" , "Kind of textbook - or its peruser" , "' -- , I married him' (J. Eyre)" .)