I think every query letter needs a one or two sentence hook. And I personally like them at the beginning.
Of course this is somewhat a matter of personal preference. Some agents may ask for other information at the beginning, in which case you should follow their directions.
But I like it at the beginning. And I have at least one other intern who’s said she also likes it at the beginning. So you know. That’s two of us. Which is more than just me.
Here’s why. The hook should be the thing that makes me care about the book, and you want me to care from the very beginning. Not like other elements of your query won’t make me care about the book, because they should. But the hook should do it best and fastest.
There are a lot of different ways to go about writing a hook. But the best hooks have two elements: something that tells me what makes the book unique, and something that hints at the voice of the book.
But bottom line, any hook that makes me want to keep reading is a good hook.
See my follow up post with examples of great hooks here.