The Book of Doom is the last book in the quest The Pen is Mightier... , its writer is unknown. When it is placed in the Academy, it floats in the air and a black field surrounds it.
The final book in "The Pen is Mightier..." is located in the (previously inaccessible) Reliquary Catacombs. You will need to find and donate all other books before Samuel gives you the Catacomb Key. Once you accept the quest, enter the first locked door on the right and then go down the stairs to the hallway on the lowermost floor. Go past the rubble of the collapsed area; the book is located on a pedestal on the right side.
If you read this book you are doomed. Don't read another line. Not another word, all right? You're still reading, aren't you? What part of 'Don't read another line' do you not understand? Well, it's too late now, you've read it. You're doomed! You never should have read this. And I probably shouldn't have written it, actually.