The Copy Book.
Not only has D&AD revised The Copy Book, they've added an extra 150 odd pages to make it look like the bible(with pictures).
It is not simply a book for writers, it's a book for anyone who's interested in the industry, how the best writers / creative directors work and think.
Which is exactly what the old book did.
So why do we need a revised version of the same book?
My guess, first of all, is to make money. I'm the target market that will buy any crap that's remotely related to the industry.
Secondly, thanks to Mad Men, there's a new breed of young masochists trying to get into the industry, and they always need authoritative figure to look up to.
So the pros: big and thick. Well worth the read and the money. People will think you're an intelligent man with taste if they see it on your coffee table.
Cons: It gets quite depressing for the owners of the first book, to see some of the 'legendary' writers demoted to freelancers 10 years later.
From an art direction point of view, the type size is bigger and easier to read.