The Murder of Roger Ackroyd

It is said that the way the story unfolded was fresh at the time, rather than the story itself.
While this type of narrative trick might not be surprising today, it is said to have surprised both readers and critics back then.
Arthur Conan Doyle even admired this work.

Since then, many works using the device of the unreliable narrator have emerged, and the prevailing opinion is that this work is the origin of it.