Is there a way to rank them objectively?

Hey gmloft,

Probably you will have to do your own research by author and title.

You can find out what native English speakers are taught in secondary school, for example, by year. Then, you can assume that "final-year" books are more difficult.

Hint: Probably Shakespeare will make the list! Emotion: smile

I am familiar with Gutenberg. I'd say the easiest are probably in the Top 100 most popular list.

There is also the University of Adelaide in Australia that has a very large selection of free ebooks.