Let best-seller adapt more literary works (6-7)

I believe the answer is:

belles-lettres

I'm a little stuck... Click here to teach me more about this clue!

'literary works' is the definition.
(I've seen this before)

'let best-seller adapt' is the wordplay.
'adapt' indicates an anagram (I've seen 'adapted' mean this).
'let'+'best'+'seller'='letbestseller'
'letbestseller' anagrammed gives 'BELLES-LETTRES'.

'more' is the link.
This may not be correct. It may belong to another bit of the clue.

Can you help me to learn more?

(Other definitions for belles-lettres that I've seen before include "Elegant literature" , "Creative writing valued for aesthetic content" .)

I've seen this clue in the Sydney Morning Herald.

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