Book is perfect, I see! (6)
I believe the answer is:
isaiah
'book' is the definition.
(I've seen this before)
'is perfect i see' is the wordplay.
'perfect' becomes 'ai' (I've seen this in other clues).
'i see' becomes 'ah' (exclamation used to indicate understanding).
'is'+'ai'+'ah'='ISAIAH'
(Other definitions for isaiah that I've seen before include "Sixty six chapter prophet" , "A philosophical Berlin" , "Book and prophet of the Old Testament" , "8th century BC Hebrew prophet" , "Biblical prophet (and his book)" .)