Randall Munroe is the author of one of my favorite web comics, xkcd, and so I was excited when what if? was chosen for our book club. And for good reason: this is the funniest book I've read in ages. I read it while traveling recently and my wife kept looking at me oddly when I'd literally laugh out loud! The concept here is that Munroe gives "serious scientific answers to absurd hypothetical questions," heavily laced with his trademark humor and cartoons. "Absurd" is certainly an appropriate word, with the book including questions such as "From what height would you need to drop a steak for it to be cooked when it hit the ground?" "How fast can you hit a speed bump while driving and live?" and "What would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place?" The author then examines the questions with a scientific bent, albeit often ridiculous as immortal people and bullets with the density of a neutron star are theoretical at best.
It is hard to pick my favorite vignette; they were all fantastic. "Periodic Wall of the Elements" discusses the possibility of building a periodic table where each block is actually made of the respective element. "The sixth row would explode violently, destroying the building in a cloud of radioactive, poisonous fire and dust. Do not build the seventh row." "Relativistic Baseball" examines a baseball being pitched at 90% of the speed of light, ending with "everything within roughly a mile of the park would be leveled, and a firestorm would engulf the surrounding city. Major League Baseball Rule 6.08(b) suggests that in this situation, the batter would be considered “hit by pitch” and would be eligible to advance to first base." And "Machine-Gun Jetpack" has possibly my favorite cartoon (included here) with the caption "Actually, what I'm confused about is how."
On top of the humor inherent in the questions and answer themselves, there is a constant stream of comedy throughout the narrative as well. Pop-culture references abound, with Gremlins, Furbies, Star Wars, Lord of the Rings, Dragon Ball Z, and Firefly making common appearances. At one point Munroe gets int an argument with himself in the footnotes about the proper capitalization and attribution of "Lego." And one of my favorite running gags was the use of  for patently obvious items: "After all, the Empire State Building sits on a base like that, and it's more than a few days old and hasn't disappeared into the ground." Even the book jacket was funny, with the flip-side showing a map of "the world after a portal to Mars opened at the bottom of the Marianas Trench, draining most of the oceans."
I can't say enough good things about this book. Funny and educational; everyone in my book club liked it, as did both of my sons. Munroe gathers these questions from his website, so hopefully a sequel is in the cards!
Q. What would happen if the Earth ad all terrestrial objects suddenly stopped spinning, but the atmosphere retained its velocity?