Worldwide Death
 

Just out of curiosity, what are some of the best books in which the whole world/human race is either dying off in the beginning, and dies in the end, or begins all nice and pretty and then everything dies in the end.

In short: if the whole world is doomed and there is NO salvation in the end, what's the title and who wrote it.:p

Kurt Vonnegut - Cat's Cradle

Pretty much fits your criteria and is definitely one of my favorite books.

There's also On The Beach by Nevil Shute. Of course, you're basically asking us to give away the ending, because you want a guarantee that nobody lives and everything's hopeless, and at least with On The Beach, there's a glimmer of hope for part of the book. Kind of ruins the suspense.

I'll also throw in The Road by Cormac McCarthy. It's more of an allegory focusing on a man and his son, and their journey through a post-apocolyptic wasteland. Granted, the book ends on an up note of sorts, but given that everything that would live (plants, animals, humans, etc.) is dead or dying in the book, with no hope that the environment will make a turnaround, and no way to grow crops or raise animals, it's doubtful that the characters will live more than a few more years before they run out of food.

I Have No Mouth and I Must Scream by Harlan Ellison, I don't want to spoil it so I'll just say that it deals with some folks living underground and a very disturbed computer. And the ending is far from happy.

I'll 2nd anything by Harlan Ellison. Btw - he revealed in an article on dreams & writing that part of that story came to him in a dream.