Thought I'd have the best chance of getting an answer from here.

I vaguely remember she was the same person who wrote King Edward for Daggerfall?

Also, has she written any other in-game books in TES series?

According to the Imperial Library, it was written http://www.imperial-library.info/content/real-barenziah-complete, a beta-tester for Daggerfall, who, if I am not mistaken, is the namesake of Mara (http://www.imperial-library.info/content/daggerfacts). She also wrote http://www.imperial-library.info/content/king-edward, andhttp://www.imperial-library.info/content/ebon-arm.

Quite naughty, that guy , if I remember the first iteration of Barenziah's books.

He's the reason I know more about certain *cough*... aspects... of Khajiit than I cared to

http://www.gamesas.com/user/944207-effehezepe/ is right about Marilyn being the real-world author. The ingame author is http://www.uesp.net/wiki/Tribunal:Plitinius_Mero.

Huh. I wonder if we'll ever hear how the story of King Edward ends. The plot just sort of cuts off. I liked those books a lot, despite the inconsistencies with later lore.