See a book spy's concealed — not secure? (7)

'concealed not secure?' is the definition.
I can't tell whether this definition defines the answer.

'see a book spy's' is the wordplay.
I cannot quite understand how this works, but
'see' could be 'v' (short for 'vide', Latin meaning 'see elsewhere') and 'v' is located in the answer.
'a' is within the answer.
'book' could be 'b' (abbreviation for book) and 'b' is located in the answer.
'spy' could be 'mole' (mole is a kind of spy) and 'mole' is found within the remaining letters.
No letters remain.
This explanation may well be incorrect...

Can you help me to learn more?