Satisfied about books for choral composition (5)
I believe the answer is:
motet
'choral composition' is the definition.
(I've seen this in another clue)
'satisfied about books' is the wordplay.
'satisfied' becomes 'met' (as in 'met the conditions of his contract').
'about' means one lot of letters goes inside another.
'books' becomes 'OT' (Old Testament).
'met' going around 'ot' is 'MOTET'.
'for' acts as a link.
(Other definitions for motet that I've seen before include "Musical composition" , "musical piece" , "work by Tallis, for example" , "Short sacred choral piece" , "Piece for choir" .)