About to present book (7)
I believe the answer is:
re-serve
'book' is the definition.
(I've seen this before)
'about to present' is the subsidiary indication.
'about' becomes 're' (regarding).
'to present' becomes 'serve' (**).
're'+'serve'='reserve'
(Other definitions for re-serve that I've seen before include "Book; retain" , "Hold back or set aside for future use" , "Husband - substitute" , "Save" , "Withhold; stockpile" .)