Tax done by the book? (8)
I believe the answer is:
overwork
'tax' is the definition.
(thesaurus)
'done by the book?' is the wordplay.
'done' becomes 'over' (I've seen this before).
'by' says to put letters next to each other.
'the book?' becomes 'work' (book is a kind of work**).
'over'+'work'='OVERWORK'
(Other definitions for overwork that I've seen before include "Excessive labour" , "Toil too hard" , "Drive too far" , "Tax" , "Toil excessively" .)