Book's self-dedication (4)

I believe the answer is:

tome

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'book's' is the definition.
(a tome is a book)

I don't understand how the remainder of the clue works.

(Other definitions for tome that I've seen before include "Big book" , "Large and scholarly book" , "Large scholarly volume" , "dictionary?" , "War and Peace, say" .)

I've seen this clue in The Daily Express and The Mirror.

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