Come to think about it, X-Ray would be extremely helpful in a series of books like J. R. R. Tokiens The Silmarillion, The Hobbit, and The Lord of the Rings trilogy. I've got all of these in ePub from the Sony bookstore (I think that is where I bought them a few years ago). I sure wish they were from Amazon with X-Ray enabled as I'm sure I'll read them all again some day. I remember stumbling all over the character and place names as they are so different from modern American English, and because they were so different it was difficult to remember them.