Into a new world
Every book is a journey into a new world. In some books that world is just much further away.
It's easy to get started with a book that is set into a real world especially if it features a setting familiar to you. Even if it has some fictional elements, is set into some historical period or even in the near future it still doesn't require that much imagination to see the world. Sure there are far away places you have never been or cultures you are not familiar with in the real world too that can give you enough distance from the ordinary.