Book that's turned up on radio (6)
I believe the answer is:
volume
This clue is a double definition.
'book' is the first definition.
(I know that book can be written as volume)
'that's turned up on radio?' is the second definition.
(you may turn up the volume of a radio)
(Other definitions for volume that I've seen before include "Book; degree of loudness" , "Loud sound or big book" , "work" , "Loudness of sound" , "Three-dimensional space occupied by something" .)