less known 和 little known 的差別在哪裡？如果不好說明，請提供一些例句。

Less known implies that there is a second subject, and that the subject you are about to mention is not a well know as the other subject.

"The musical group, "Break of Reality" is generally less known than the group "Vitamin String Quartet"

With "little known" there is only one subject, and you are talking about the degree at which it is known.

"It is a little known fact that it took Leo Tolstoy six years to write his novel War and Peace."