So, one thing I've always wondered is this: how come Tolkien (or Lewis, as well) aren't published under Harper Voyager? They are instead published just under "HarperCollins".

Every other fantasy series by Harper is under the Voyager banner, such as A Song of Ice and Fire by George R.R. Martin, and The Realm of the Elderlings by Robin Hobb.

Just curious why Tolkien isn't part of that.