"This is an extract of the book War and Peace," is what I would have always said, but recently I was told it should be " an extract from". Can anyone give me a definitive answer to this?
But "extract" is not being used as a verb, but as a noun, here. Sure, "from" works in both cases, but you would hardly say "This is an extract out of a book."
If you made an extract of War and Peace, you would presumably boil the book in a pan overnight and then simmer until most of the liquid had evaporated.
If you made an extract of War and Peace, you would presumably boil the book in a pan overnight and then simmer until most of the liquid had evaporated.