Keen to get hold of book displaying brilliance (7)
I believe the answer is:
lambent
'displaying brilliance' is the definition.
I can't judge whether this definition defines the answer.
'keen to get hold of book' is the wordplay.
'keen' becomes 'lament' (keen can mean to wail with grief).
'to get hold of' is an insertion indicator.
'book' becomes 'b' (abbreviation for book).
'lament' placed around 'b' is 'LAMBENT'.
Can you help me to learn more?
(Other definitions for lambent that I've seen before include "Flickering like malt, Ben" , "shedding some light" , "Shining example" , "Making stealthy moves" , "inflamed?" .)