What would happen if absolutely everyone jumped at the same time? How could we build a Lego bridge between London and New York? What if my DNA vanished? How long could a submarine last in space? What are the odds of meeting my soulmate? In pursuit of answers, Munroe runs computer simulations, pores over stacks of declassified military research memos, solves differential equations and consults everyone from astronauts to nuclear reactor operators. His responses are masterpieces of clarity and hilarity, complemented by comics. (They often predict the complete annihilation of humankind, or at least a really big explosion.) Welcome back to the mind-blowing world of WHAT IF? ... Now with 10 x the science and 10 x the jokes. Featuring brand-new 2-colour annotations and illustrations, this special anniversary edition will leave you feeling much smarter, whether you have a Nobel Prize or not. 'Randall Munroe is nerd royalty.' - Ben Goldacre.