Uplifting study by Rex Russell gained through his work (6)
I believe the answer is:
earned
'gained through his work' is the definition.
'earned' can be an answer for 'gained' ('earn' can be a synonym of 'gain'). I'm not certain of the 'through his work' bit.
'uplifting study by rex russell' is the wordplay.
'uplifting' says the letters should be written in reverse.
'study' becomes 'den' (term for a study or office).
'by' says to put letters next to each other.
'rex' becomes 'R' (abbreviation e.g. GR=George Rex, King George).
'russell' becomes 'ae' (I've seen this in other clues).
'den'+'r'+'ae'='denrae'
'denrae' backwards is 'EARNED'.
Can you help me to learn more?
(Other definitions for earned that I've seen before include "Obtained through work" , "Merited through work" , "well deserved" , "Acquired through work or effort" , "Merited through behaviour" .)