My sister gave me the website for AR (she's a middle school teacher) and I looked up as many books as I could find so I could incorporate the recommended grades/reading levels. It's not as easy as it sounds. Just as an example, remember your beloved copy of The Wizard of Oz? It's listed as Middle Grades, IE grades 4 to 6, but at a 7th grade reading level. Oh my, no wonder there's a number of retellings that simplify the original language!
And you know, I kinda don't approve of "dumbing down" these classic books. I also don't approve of "cleaning up" the language -- good, bad and ugly -- in books written and set in a particular era. I think we need to remember the ugly parts of our history, including the language, attitudes and racism of those times.
Please don't think I'm comfortable with those terms -- I'm not. But I'm old enough to remember when people thought that it was OK to use derogatory words toward our Brothers and Sisters of Color, for no other reason than, well, they could. I'm forever grateful for the Civil Rights movement, knowing that in all too many ways, that vision of equal rights for all continues into the present and on into the future.
The AR web address: http://www.arbookfind.com/default.aspx