I once read a recent interview with a thriller writer where the interviewer was asked about hooks. The writer said that there needs to be a major hook at the end of every chapter, to pull the reader into the next and beyond.
He is dead wrong--no pun intended.
If there were major hooks at the end of every chapter, the reader would get exhausted and be forced to quit reading. Take your favorite bestselling thriller writer (not that the one in the interview wasn't--no offense but he wasn't as well known as John Sandford or James Patterson) and examine any one of their thrillers. Where are the hooks? In every single chapter? Nope.
Didn't think so.
The key is to sprinkle hooks throughout your book, without it seeming like there is one around every corner. This may be a piss-poor answer, but there should be just the right amount of hooks, not too many and not too few.
What is a hook?
In its simplest forms, a hook is a plot technique that draws the reader to continue reading the story. This is typically at the end of chapters--but not every one.
Also, a hook should move the story along, not be some gimmick. Don't end your chapter with, "And he opened the door and saw . . ." Only to open the next chapter with, "His mother, holding a birthday cake. And it wasn't even his birthday."
In Stephen King's 11/22/63 he ends with one of his chapters with the main character stepping through the portal, from 2011 to 1958. That's it. No gimmick. Just plain, awesome writing. And does every chapter end with a hook? Nope.
Chances are, you know what hooks are, you just had to put a name to the technique. Once again, I stress not to put hooks at the end of every chapter. Hooks shouldn't be what drives a reader to read your story. If you build your characters well enough and your readers will like them, they'll read it.