Crossword Genius

The bad girl reverted, in the book (6)

Ross

I believe the answer is:

manual

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

'book' is the definition.
(I know that manual is a type of enchiridion)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for manual that I've seen before include "Operated by hand" , "Involving human effort" , "Relating to the hands" , "Handy" , "Done by hand, or a handbook" .)

I've seen this clue in the Evening Standard.
Want a hint initially instead of a full solution? Install my app