One keeping books in balance fled having concealed one (9)

I believe the answer is:

librarian

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'one keeping books' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

'balance fled having concealed one' is the wordplay.
'balance' becomes 'libra' (the Scales in the zodiac).
'fled' becomes 'ran' (ran away).
'having concealed' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'ran' enclosing 'i' is 'rian'.
'libra'+'rian'='LIBRARIAN'

'in' is the link.

Can you help me to learn more?

(Other definitions for librarian that I've seen before include "Custodian of a collection of books" , "Philip Larkin was one at Hull University" , "One dealing with books" , "Browsers need her" , "Person working with books" .)

I've seen this clue in The Times.

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