Finally gives book required for geography to head teacher (6)
I believe the answer is:
atlast
'finally' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'book required for geography to head teacher' is the wordplay.
I cannot really see how this works, but
'book' could be 'atlas' (atlas is a kind of book) and 'atlas' is present in the answer.
A single letter 't' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'gives' is the link.
Can you help me to learn more?
(Another definition for atlast that I've seen is " ultimately".)