Spy's family provides material for notebooks! (8)
I believe the answer is:
moleskin
'provides material for notebooks' is the definition.
I can't tell whether this defines the answer.
'spy's family' is the wordplay.
'spy's' becomes 'mole's' (mole is a kind of spy).
'family' becomes 'kin' (synonyms).
'moles'+'kin'='MOLESKIN'
Can you help me to learn more?
(Other definitions for moleskin that I've seen before include "Thick piled cotton cloth" , "Fur resembling velvet" , "source of warmth" , "Strong cotton fabric with soft nap, used for work clothes" , "Type of fur" .)