http://www.tamriel-rebuilt.org/?p=books§ion=183041

I don't know which mod added this book to Oblivion, but I think it was Oscuros Oblivion Overhaul. I'm almost sure it didn't exist in-game before I installed mods.
Anyway, when I search for it on the Imperial Library and UESP, it doesn't show up, and I can only find it on other sites.
At first I thought the book had been taken from Morrowind, but that doesn't seem to be the case.
Does anyone know who wrote this book? It looks rather professionally done by me. And if it's written by a developer, is it canon? Does anyone know?

Thanks in advance!

No, it's not. If it's not listed on The Imperial Library under the book sections, it's not canon. That doesn't mean it's wrong, though, just that Bethesda could define it themselves in later games without reference to this, and this source would cease to be credible.

The standard test of canon is "if it violates Bethesda defined lore, it's not right. If it doesn't, it may be right, but it's still not canon."

It is a very good book, though, and uses a lot of good canon information to predict something. So you can treat it as canon, but recognize that it may not stand as canon if Beth were to change it (which is highly unlikely at this time).

THat particular book commonly circulates among a number of different mods. I've seen it in Castle Dunkerlore, a little mystic archives mod I snagged way back when, and numerous others. No idea who the original creator of it's content was, but it's definitely not a official work.

So, short answer:

1. Is it canon: no.
2. Is it lore: same as above, no.
3. Is it sensible: only if the underlying assumptions the author made are correct.

It was originally written by Xui'al, one of Tamriel Rebuilt's literature moderators back in the day. It was part of TIL as a forum scholar's guild article until the move.

/\ what lady N said. As i was reading it again i was like, "I've definitely read this on the old TIL"

Thank you for the information, all of you!

So it's not canon, and written by a fan. Like you say SkyShadowing, it's a damn good book though. Xui'al did a good job.