We had a quick google and Amazon gave us these five books that were top sellers in 2016.
5. The Girl On the Train by Paula Hawkins.
4. The Midnight Gang by David Walliams
3. Lean in 15 - The Shape Plan: 15 Minute Meals With Workouts to Build a Strong, Lean Body by Joe Wicks
2. Harry Potter and The Cursed Child by J.K. Rowling
1. Lean in 15: 15 Minute Meals and Workouts to Keep You Lean and Healthy by Joe Wicks
So if you don't own any of these, then maybe with that Christmas money you should go and invest!