Strange approach taken about year books (9)
I believe the answer is:
apocrypha
'books' is the definition.
(I've seen this before)
'strange approach taken about year' is the wordplay.
'strange' indicates anagramming the letters.
'taken about' means one lot of letters goes inside another.
'year' becomes 'y'.
'approach' anagrammed gives 'apocrpha'.
'apocrpha' going around 'y' is 'APOCRYPHA'.
(Other definitions for apocrypha that I've seen before include "religious text" , "Old Testament books rejected in Judaism and excluded from Protestant Bible" , "Woodwind player" , "Doubtfully-authentic writings" , "set of disputed writings" .)