How I define my top 10 will definitely differ from others'. When I try to recollect the best books I've ever read, I have this criterion. How much did that book force me to finish in one go? Whether I was able to finish it in a single go or not due to other compelling reasons. Secondly, how much was I able to connect earlier chapters while reading later chapters. At times it happens you are at the end of the book but are not able to connect well with the story and flow. Third and most important point is how much did it fade away from my memory over a period of time. There are so many books that are as fresh in my mind as at the time of reading them. And there are books that you forget about within a week of finishing them.