American can't get over Dracula is very familiar with The Book of Numbers (10)
I believe the answer is:
Here is my best explanation:
'very familiar with the book of numbers' is the definition.
I can't judge whether this defines the answer.
'american can't get over dracula' is the subsidiary indication.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'get' is an insertion indicator.
'over dracula' becomes 'count' (I am not sure about the 'over' bit.**).
'cant' placed around 'count' is 'ccountant'.
'is' is the link.
(Other definitions for accountant that I've seen before include "One keeping track of money", "auditor", "One dealing with finances", "Financial expert", "He scores", "fellow cutting costs?", "Bookkeeper, maybe chartered" and "financial controller".)