He's engaged by stars to produce book (9)
I believe the answer is:
thesaurus
'book' is the definition.
(thesaurus is a kind of book)
'he's engaged by stars' is the wordplay.
'engaged by' is an insertion indicator (I've seen this in other clues).
'stars' becomes 'taurus' (I've seen this before**).
'hes' placed inside 'taurus' is 'THESAURUS'.
'to produce' is the link.
(Other definitions for thesaurus that I've seen before include "Wordy book" , "Dictionary" , "lists?" , "storehouse" , "work we may refer to" .)