Modernist Cuisine: The Art and Science of Cooking, by Nathan Myhrvold, Chris Young, and Maxime Bilet, is a $625 cookbook (actually it's $421.87 on Amazon, with free shipping!). That is very, very expensive, and some folks are understandably shocked by the price. That's okay, though, because the five volume, 2,200-page guide to molecular gastronomy is not really intended for them. Like not at all.
Modernist Cuisine is written for the particular subset of professional chefs who toy with the science of food. The tools required for their craft can be very expensive: for example, an immersion circulator used for sous vide cooking or a centrifuge can both cost anywhere from $1,000 to $3,000 (all prices used in this post are from Amazon). Or much more. (These prices are not exclusive to molecular gastronomy equipment; commercial stoves cost upwards of $4,000, for example, and professional blenders cost between $400 to $500.) There is significant value in thoroughly exploring the capabilities of such equipment after such a large investment.
Also, compared to texts and guides for related industries, the price is comparable. For example, The Theory of Catering is $750, and the 2,099 page Food: Critical Concepts in Social Sciences goes for $1,495. That doesn't make the price excusable, but it does demonstrate that it's not unheard of for professional texts to cost as much or more than Modernist Cooking.
But still. Why is it so expensive? Other chefs in this field have produced cookbooks for far less money: The menu catalogs for Ferran Adrià's El Bulli cost between $200-$300 for example, and Heston Blumenthal's epically huge The Big Fat Duck Cookbook runs around $250. So what are you getting in Modernist Cuisine that's worth an extra three, four hundred dollars?
The research and execution of the book was organized by Nathan Myhrvold, a former chief technology officer for Microsoft and the founder and CEO of Intellectual Ventures, a firm which invests in inventors. Myhrvold along with Chris Young and Maxime Bilet, both former chefs in Blumenthal's research kitchen for the famed restaurant The Fat Duck, hired a staff of 20 people to initially research the sous vide cooking technique, and instead ended up with a massive multi-volume text that also covers "microbiology, food safety, the physics of heat transfer on the stove and in the oven, formulas for turning fruit and vegetable juices into gels, and more." The creation of what they call The Cooking Lab as well as the development of promised new photographic techniques adds to the cost. Also because of its lack of mass appeal, Myhrvold and company are self-publishing in vastly smaller numbers than even, say, Thomas Keller's $47 professional sous vide cookbook Under Pressure.
So who will buy it? Certainly professionals, culinary schools, and perhaps even more progressive traditional university chemistry departments. That's not to say non-professionals won't buy it: there are plenty of food-obsessed folks with money to burn who would love nothing more than to have Modernist Cooking on their bookshelves, pristine and untouched. Is that silly? Sure. Is it hurting anyone? Not really.
A commenter on the Gawker piece cited above said, "I'd rather spend the $600 on good products, or, better even, a good restaurant." Which is great! And this book could be the key to the dishes one might consume at such an expensive meal. The research and the techniques and the knowledge have the potential for a lasting impact; David Chang has called it "the cookbook to end all cookbooks" and Ferran Adrià said "This book will change the way we understand the kitchen." That sounds like it might be worth $625.