What has the author Alan S Walker written?

It seems you're thinking of the *musician* Alan Walker, not an author.

Alan Walker is a Norwegian DJ and record producer, known for his electronic dance music. He's known for songs like:

* Faded

* Alone

* On My Way

* The Spectre

* Tired

* Darkside

He's released several albums and EPs, and is a popular figure in the EDM scene.

If you're interested in a different Alan Walker, please let me know and I'll be happy to help you find information about them!