Alright, alright, alright! You ask (and ask, and ask again), we answer. The font used on the artwork of How to dismantle an atomic bomb is called Clarendon. And no, we cannot provide you with it, but you can buy it from your local Type shop.
This modern serif was designed in 1953 by Hermann Eidenbenz and is currently owned by the Bitstream foundry. It’s become rather popular on- and offline recently. Starbucks are using it. In fact it’s so popular that web guru Jeffrey Zeldman exclaimed: ‘Clarendon is the new Helvetica‘.
Here’s a helpful link for all your future font questions: ‘What the Font?‘ will help you determine what typeface is used by uploading a scanned image.