A last edition of a book (5)

I believe the answer is:

atlas

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

'book' is the definition.
(atlas is a kind of book)

'a last edition' is the wordplay.
'a last' can be anagrammed to 'ATLAS'.
But, I am unsure how this is indicated.

'of a' is the link.

Can you help me to learn more?

(Other definitions for atlas that I've seen before include "collection of charts" , "God" , "In Greek myth, a Titan made to support the heavens" , "Sky-toting Titan" , "I carry a huge weight" .)

I've seen this clue in The Globe and Mail.

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