Content in schedule affected - that's one for the books (4)
I believe the answer is:
leaf
'one for the books' is the definition.
I can't judge whether this defines the answer.
'content in schedule affected' is the wordplay.
'content' indicates the answer is hidden within the clue (I've seen 'content of' mean this).
'LEAF' is hidden within 'in schedule affected'.
'that's' is the link.
Can you help me to learn more?
(Other definitions for leaf that I've seen before include "Sheet of paper" , "Flick (through)" , "Page - part of a plant" , "Bit of tree, of book" , "Frond" .)