The data for the book on textiles? (8)
I believe the answer is:
material
'the data' is the definition.
(thesaurus)
'book on textiles?' is the wordplay.
I cannot really see how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is found within the answer.
This explanation may well be incorrect...
'for the' acts as a link.
Can you help me to learn more?
(Other definitions for material that I've seen before include "Relevant - fabric" , "grave" , "Stuff - relevant" , "Directly relevant to a matter, in a law case perhaps" , "it is of some significance" .)