Fun Fact: "Ten Little Indians" was originally titled "Ten Little Niggers" but they decided "Indians" was less offensive enough to allow it to stay in libraries.
The title was changed in the U.S, but in the U.K. it was called "Ten Little Niggers" well into the '90s. The story took place on "Nigger Island"; all such references were edited out.
I have a mid-80s copy of "Ten Little Niggers." It's not any more offensive than (say) Mark Twain's "Nigger Jim," who was by far the smartest guy in the Huck Finn / Tom Sawyer books. Those were just very different times, and the writing has to be taken in context.