Books you couldn't put down?

What are some books that you've read that you absolutely couldn't put down?

When I was a teenager, I had obsession with harry potter. I read last book in one day (700+ pages). That's my greatest achievemnt when it comes to reading books.

Stoic wrote:

When I was a teenager, I had obsession with harry potter. I read last book in one day (700+ pages). That's my greatest achievemnt when it comes to reading books.

The Harry Potter series is one example of books that I've read quickly, especially the 3rd one. I stayed up late one night to finish the 3rd book but luckily I didn't have to go to work the next day.